Opthalmologic therapy system and method for processing a portion of a processing volume of a transparent material by application of focused radiation

ABSTRACT

A system for processing a portion in a processing volume of a transparent material by application of focused radiation including a device for generating and an optical system for focusing radiation, with a device for changing the position of the focus of the radiation and a control device. The system includes a controller that controls the ophthalmologic therapy system. The controller is encoded with a scan pattern. The scan pattern includes adjacent strokes with each adjacent stroke having an angle of inclination (α) to the beam axis; and the angle of inclination (α) of the strokes to the beam axis is always larger than or equal to the focal angle (φ) of the focused radiation.

RELATED APPLICATIONS

This application is a continuation of application Ser. No. 15/742,233,filed Jan. 5, 2018, entitled “Opthalmologic Therapy System and Methodfor Processing a Portion of a Processing Volume of a TransparentMaterial by Application of Focused Radiation,” which is a National Phaseentry of PCT Application No. PCT/EP2016/066033 filed Jul. 6, 2016, whichapplication claims the benefit of priority to German Application No.102015212877.6, filed Jul. 9, 2015, the entire disclosures of which areincorporated herein by reference.

BACKGROUND

The present invention relates to a system for processing an area in aprocessing volume of a transparent material by application of a focusedradiation, which contains a device for generating radiation, an opticalsystem for focusing the radiation into a focus in the processing volume,a device for changing the position of the focus in the processing volumeand a control device arranged to control the system. The presentinvention further relates to a corresponding method for processing anarea in a processing volume of a transparent material by application ofa focused radiation and a control program product and a planning unitfor a system or a method for processing an area in a processing volumeof a transparent material by application of focused radiation.

Such a device can be used in ophthalmology as an ophthalmologic therapydevice, corresponding methods can be used as ophthalmologic therapymethods. The transparent material to be processed can thereby be anatural eye tissue, for example the lens, the cornea or the capsularsac, or even an artificial eye material, such as an artificial lens.

To date, so-called spiral scans are customary. These are described forexample in the documents U.S. Pat. No. 5,984,916 and DE 10 2011 085 047Al, an exemplary embodiment is shown in FIG. 1. A laser beam 1 isfocused by an optical system 2, 201 in a transparent material 3. Thefocus 4 is thereby moved by a scanning system along a scan line 5, whichis spirally here due to a lateral arbitrary closed movement such as arotational movement, and a slow z-movement of the scanning system,through a transparent eye tissue 3. The optical system 2, 201 therebydetermines the shape of the focal cone 6. In order to be able to usesuch a spiral scan for processing the eye tissue 3, the lateral areareachable by the optical system 2, 201 must be large enough to reach allprocessing areas without slow lateral movement of the optical system 2,201. The optical system 2, 201 is correspondingly large and expensive.Due to the necessary size, this method is also only conditionallysuitable for use in flexible, mobile devices with an articulated arm.

Incisions with a femtosecond laser are also known which are implementedin the vertical direction by fast scanning movements. This is calledvertical z-wobble and is described for example in document WO2013/057318 A1. FIG. 1b shows a schematic exemplary embodiment of thez-wobble. A laser beam 1 is also focused here in a transparent material3 by use of an optical system 2, 202. The focus 4 is thereby movedthrough a scanning system along a scan line 5, which is generated hereby a periodically recurring, fast scanning movement in the z-directionwhich is superposed with a slow scanning movement in an x-y plane,through a transparent eye tissue 3. Such movement for processing eyetissues 3 by use of a laser scans allows a smaller optical system 2,202, as the fast movements are respectively carried out in a smallvolume. However, in unfavorable incision or processing patterns, thealready generated vertical incision lines or processing lines alreadypartially overshadow the laser focus 4 for incision lines to be appliedclosely adjacent thereto.

The aim is therefore to describe an apparatus and a method forprocessing an area in a processing volume of a transparent material,allowing it to work with a cost-efficient, thus small optical system andminimizing shadowing effects of the previously carried out incisionlines or patterns in the laser focus for yet to be producing incisionlines or patterns.

A possibility is provided by the lateral wobbling as disclosed in thedocuments EP 2412341 B1 or EP 2596773 B1 in an x-y plane.

Starting with such fast, for example oscillating lateral movements, ageneration of a plane which proceeds parallel to the z-axis, is nowpossible by adding a small z-movement, as shown in FIG. 2. A laser beam1 or another radiation is again focused by an optical system 2, 202 in atransparent material 3. The focus 4 is thereby moved by a scanningsystem along a scanning line 5, which is produced here by a periodicallyrecurring, fast lateral scanning movement which is superimposed with aslow scanning movement in a z-direction, through a transparent eyetissue 3. Here, for example, a cylindrical incision with significantlocal z-extension, i.e. an extension in the z-direction which is largerthan the effective area of a laser focus and thus requires several scanswith the focus 4 arranged above one another, and having a lateralextension which is larger than the (partial) field, that cansimultaneously be achieved with the optical system 2, 202 withoutadditional lateral movement, can be assembled of several “patches”, thuspartial processing areas, in order to be able to utilize the speedadvantage of the lateral wobbling. Such a procedure of “patching” isnecessary when using the lateral wobbling in ophthalmology for a numberof treatment patterns, particularly of incision images such as thecylindrical incision of the capsulotomy.

A lateral wobbling is possible with a system which allows a fastscanning in a plane of a processing volume perpendicular to a beam axisplane.

The assembly from several partial processing areas, however, producesmany border regions 501, in which two adjacent partial processing areashave to be aligned to each other, such that, on the one hand, no“processing gap” results, and, on the other hand, regions, for whichthis is not intended, are not processed twice. It also leads tosituations in the peripheral areas of the partial processing areas wherea shadowing effect by already produced incision or processing linesbecomes unavoidable.

SUMMARY OF THE INVENTION

Example embodiments of the present invention describe a system and amethod, especially for ophthalmology, for processing an area in aprocessing volume of a transparent material by application of a focusedradiation, which permits working with a cost-efficient, thus smalloptical system, with which, however, the processing of the area iscarried out with highest quality. In particular, shadowing effects ofthe processing lines or patterns already generated, also referred to asscan line or scan pattern herein, for processing lines or patterns stillto be generated are avoided or at least minimized, boundary regions thatare difficult to align to each other between two partial processingareas are minimized and area forms with a greatest possible flexibilityare expected to be generated. The risk of damages to the processedtransparent material shall also be minimized.

Example embodiments of the invention include a system and a method forprocessing an area in a processing volume of a transparent material, inparticular an eye by a control program product and by a planning unit.

A system is designed for processing an area in a processing volume of atransparent material, in particular of an eye, by application of focusedradiation. The system may thus for example be an ophthalmologictherapeutic system, which is used in ophthalmology for example forophthalmologic surgical purposes, or for irradiation. However, thesystem is not restricted to ophthalmology according to itscharacteristics and functional principles, as can be seen from theexplanations.

The processing area can be a two-dimensional area in a three-dimensionalprocessing volume. However, the area may also comprise an additionalcurvature, thereby forming an area, which is a three-dimensionalstructure. In particular, the area may be a closed area in athree-dimensional processing volume.

A special case of an area to be processed is the formation of an “area”for generating a processing line in such a manner that this “area” issignificantly extended in at least one spatial direction and has aminimum extension in at least one other spatial direction. Such an“area” serves for example for the opening of thin structures, inophthalmology the implementation of a capsulotomy shall be mentioned asan example.

The processing area may be a separation area or an incision area.However, it may also be an area, on which the transparent material isremoved or changed in its material properties, for example adhered.

A transparent material is a material that has only a small, virtuallynegligible, linear absorption in the wavelength range of the radiationused, so that an additional measure, for example, the focusing of theradiation, is required in order to generate an effect in this material.

The transparent material to be processed may be an eye tissue, as forexample the cornea, the lens, the lens sac or the vitreous body.However, it may also be an artificial material, in particular anartificial eye material, such as an intraocular lens (IOL) at which areto be made corrections. The material to be processed can be of organicor inorganic nature.

The system comprises a device for generating radiation. This may be anappropriate light source or another radiation source that emits afocusable radiation. The device for generating a radiation may inparticular comprise a laser, thus a device for light amplification bystimulated emission of radiation. Such a laser produces light of highintensity, usually from a narrow frequency range, with a high spatialcoherence.

The use of a pulsed laser is advantageous, in particular a short pulselaser such as a femtosecond laser (fs laser) for generating afemtosecond laser beam or a picosecond laser. A pulsed laser emits lightin time-limited portions, thus not continuously. It provides a highenergy density.

Such a femtosecond laser or picosecond laser, for example, can herebyhave a wavelength in the wavelength range from 200 nm to 2000 nmwavelength: water or eye tissue have a low linear absorption in thisarea and are thus a transparent material for the radiation of afemtosecond laser or picosecond laser.

Femtosecond lasers commonly in use today, which are to be used here,have a wavelength in the range of 750 nm to 1100 nm. The use offemtosecond lasers, which have a wavelength in the range of 375 nm to550 nm or in the range of 250 nm to 367 nm, which corresponds to adoubling or tripling of the frequency of the usual femtosecond laser isalso conceivable. In particular, a femtosecond laser from the wavelengthrange of 1020 nm to 1060 nm is used here by way of example.

The pulse duration of a femtosecond or picosecond laser, which is usedhere, can advantageously be chosen from a pulse duration range from 50fs to 5 ps. In particular, a pulse duration from a range from 100 fs to1 ps, and particularly from a range from 300 fs to 700 fs is preferredhere.

The pulse energy of a femtosecond or picosecond laser used here isadvantageously in a pulse energy range from 20 nJ-200 μJ.

The laser pulse repetition rate, thus the repetition rate of the laserpulses is usually chosen from a range from 10 kHz to 10 MHz, a laserpulse repetition rate from a range from 100 kHz to 1 MHz isadvantageous.

The system further comprises an optical system for focusing, i.e. forbundling the radiation in a focus in the processing volume. The focalcone of such a focused radiation has a focal angle. It characterizes theaperture angle of the focus, that is, an angle of divergence, which canin principle also be expressed by the numerical aperture. The focalangle describes the angle between a line extending on the cone area ofthe focal cone and the optical axis. The focal angle defined in thismanner thereby corresponds to half the cone angle of the focus cone. Forexample, the focal angle is kept approximately constant during the laserprocessing, also at various depths in the transparent material to beprocessed, as the focal length and thus the required laser pulse energyfor the desired effect depends on the focal angle.

The optical system for focusing the coherent radiation in a focus allowsa field of view in the processing volume with a field of view sizecaused by the optical system.

In the first instance, it is advantageous to be able to work with alarge field of view, as the complete target field and thus the entireprocessing volume can then be achieved without the displacement of theoptical system. An enlargement of the optical system however leads toincreasing production costs of this optical system and would thussignificantly increase the price of a system for processing an area in aprocessing volume of a transparent material.

A cost-efficient system for processing an area in a processing volumethus has a field of view size which is less than the maximum extensionof an x-y-plane of the processing volume. The maximum extension of anx-y-plane of the processing volume is achieved only by the movement ofthe optical system, and thus by the movement of the field of view.

The focused radiation has a beam axis. It is the symmetry axis of thefocused radiation and its focus cone.

The system further comprises a device for changing the position of thefocus in the processing volume, which can be described by three spatialdirections x, y and z. Here, the x-direction and the y-direction aslateral directions extend non-parallel to each other and respectivelyperpendicular to a base position beam axis, and the z-direction extendsparallel to the base position beam axis, wherein the base position beamaxis denotes the beam axis of the focused radiation without a deflectionof the focus through the device for changing the position of the focusin the processing volume in the two lateral directions x and y.

Changing the position of the focus preferably is carried outcontinuously, but not necessarily with a constant speed.

A processing volume described by the circular coordinates R and Φ andthe direction z extending parallel to the base position beam axisdirection or a processing volume described by spherical coordinates isthereby a processing volume that can be described by three spatialdirections x, y and z, too: All three-dimensional coordinate systems canalways be converted to one another.

The processing of an area in the processing volume is achieved bychanging the position of the focal point of the focused radiation withinthe processing volume. At the location of the focal point of the focusedradiation, an effective zone of this focused radiation occurs in thetransparent material, which is referred to as focus effective zone: Atthe focal point and in a next surrounding around the focal point, thefocused radiation changes the material transparent for a correspondingunfocused radiation.

For example, when using pulsed laser radiation and a constant speed ofchanging the focal position, thus the scanning speed, focus effectivezones in an even distance which is determined by the pulse rate result.In a variable scan speed and a constant pulse rate of the pulsed laserradiation, the distance of the focus effective zones varies.

As a rule, a processing area comprises a plurality of focus effectivezones distributed over the entire area, which maximally have such adistance from each other that the intended effect by the influence ofthe focused radiation is not interrupted. This leads to thecorresponding processing result along the area to be processed, like an“incision” by separating the transparent material, for example by photodisruption, to a removal of material by ablation, or a change of thematerial, for example a bonding by coagulation of the material in thefocus effective zones of a pulsed laser radiation.

The system provides the possibility to process a transparent materialwithin the processing volume. Thus, the processing volume represents thespatial area within which the system can carry out the processing of thematerial based on its possibilities for spatial change of the focalpoint of the focused radiation, which thus represents a mobile operatingpoint. The transparent material to be processed or the part of thetransparent material to be processed is thereby ideally completelysituated in the processing volume.

The system also comprises a control device which is adapted to controlthe system, in particular for controlling the device for generating aradiation, the device for changing the position of the focus of thefocused radiation and/or the optical system. For that reason, it isconnected to the device for generating a radiation, the device forchanging the position of the focus of the focused radiation and/or theoptical system via corresponding communication paths. The control devicecan be designed in one part or in multiple parts. In a one-piece designit comprises a controller, from which all parts of the system arecontrolled or operated. If it is designed in several parts, it maycomprise several controlling or operating devices, which are connectedto each other.

The control device can be encoded with a control program product, or tobe encoded with a control program product that is either on a datacarrier, wherein the data carrier is brought in connection with thecontrol device for the purpose of encoding, or the control programproduct is provided via the internet or via any other external storagespace for download, wherein the control device can connect to theinternet or to another external storage space in a direct manner or viaintermediate steps.

A planning unit as a delimiting partial unit can thereby be comprised inthe control device, which is designed to implement all steps of theplanning or provision of a therapy guidance, in particular of parametersof the beam generation, the focus as well as of scan movements forprocessing an area, in a chronological sequence. The planning unit isdesigned to plan and/or to provide a scan pattern as temporal change ofthe position of a focus of the radiation and thereby of focus effectivezones in the material to be processed.

With a control device in several parts, such a planning device can alsorepresent a unit which is independent from other units of the controldevice, and which is connected to the other units of the control devicevia communication paths.

In one embodiment, the planning unit may comprise a selection table ofscan patterns. In another configuration, it comprises an algorithm forcreating a scan pattern.

If a control device containing such a planning unit is encoded, the scanmovements, in particular the scan pattern, are provided by this planningunit.

According to the invention, the device for changing the position of thefocus of the system is designed to perform, in an arbitrary directiondetermined by the three spatial directions, a slow scanning movement inthe processing volume of the transparent material and—also in anarbitrary direction determined by the three spatial directions—a fastscanning movement independent of the slow scanning movement in a sectionof the processing volume. The section of the fast scanning movement canthereby be moved by the slow scanning movement in the entire processingvolume. Thus, a complete fast three-dimensional scanning systemcooperates with a slow independent three-dimensional scanning system insuch a manner, that the fast three-dimensional scanning systemrespectively accesses a partial section or a partial volume of theentire processing volume. This partial section can however be movedthrough the entire processing volume with the help of the slowthree-dimensional scanning system.

The possible size of the section of the fast scanning movement isdetermined by the field of view of the optical system that is used, butalso by the type of the generation of the fast scanning movement.

The terms “slow” and “fast” are defined here relative to one another andare used to identify the two base scanning movements and scanningsystems. The fast scanning movement is carried out with a maximum speed,which is a multiple of the maximum speed of the slow scanning movement.For example, the fast scanning movement may be ten times to a thousandtimes of the slow scanning movement. A fast scanning movement that isabout one hundred times of the slow scanning movement is advantageous inanother example.

Typical sizes of the processing volume in which a slow scanning movementis carried out, can, for a processing device, which is used for exampleas an ophthalmologic therapy device, be in any spatial direction between2 mm and 25 mm, for example, between 5 mm and 12 mm. This volume cantypically be scanned with speeds in a range from 1 to 100 mm/s, forexample, of about 10 mm/s.

A typical size of a section simultaneously accessible by the fastscanning movement is between 0.5 mm and 2 mm in any spatial direction.For example, a three-dimensional section of about 1 mm×1 mm×1 mm can beachieved by the fast scanning movement. Scanning movements of severalhundred Hertz are possible thereby.

The arbitrary, changeable direction determined by the three spatialdirections results for the fast and for the slow scanning movement byvector addition of the respective scanning parts in the three spatialdirections x, y and z per time unit for the fast scanning movement andfor the slow scanning movement. By vector addition of the direction ofthe fast and the direction of the slow scanning movement for the sametime unit, a total direction of the two scanning movement's then resultsfor this time unit.

The system according to the invention thereby permits on the one hand toscan a section of the processing volume at a high speed and to scan thetotal processing volume at a significantly slower speed: A focus of thefocused radiation movable through the processing volume with a slowscanning movement in an arbitrary and changeable direction during thecourse of a scanning process corresponding to a desired pattern istherefore subject to an additional fast scanning movement in a secondarbitrary, changeable direction which is superposed with the slowscanning movement during the course of the scanning process. Thisadditional fast scanning movement is, however, always only allowed in asmall section of the processing volume.

The high speed at which the fast scanning movement is carried out,additionally allows, when using a pulsed laser from the picosecond orfemtosecond range, which has a high laser pulse repetition rate, todistribute the focus effective zones correspondingly in the processingvolume and to position them not too close to each other.

This “division of labor” between slow and fast scanning movement permitsto use scanning systems for the fast scanning movement, which arecapable to change the position of the focus extremely rapidly, as theydo not have to move any large, heavy optical system, while the opticalsystem can be moved with the slow scanning movement with other scanningsystems.

A system, for example an ophthalmologic therapy system, comprises acontrol device, in which a scan pattern is encoded, which has a sequenceof focus effective zones of the focused radiation along a scan line. Thesequence of focus effective zones is thereby encoded in an advantageousembodiment of the system according to the invention such that focuseffective zones that have already been realized are always arrangedoutside a focal cone for focus effective zones still to be realized, thefocal cone being described by the focus of the focused radiation and thefocal angle.

Herein, the scan line is the line or the track that results or wouldresult, when the focus of the focused radiation, and thus also the focalcone, is moved by application of the device for changing the position ofthe focus in the processing volume, and it is or would be a continuousradiation. The scan line can be a straight line, or else be curvedeither completely or partially in a plane or in a three-dimensionalspace.

The scan line thus describes the location of the focus in the processingvolume reached during the scanning process in dependence on the time,regardless if the focused radiation just comes into effect or does notcome into effect. The actual focus effective zones of the focusedradiation are then set along the scan line.

Thus, when scanning, the focal cone is guided on a scan line through theprocessing volume in such a manner that the focal cone never intersectsthe part of the scan line already covered, then the condition that focuseffective zones that have already been realized are always arrangedoutside of a focal cone for focus effective zones yet to be realized, isfulfilled in any case. But the condition can also still be fulfilled,if, during scanning, positions result, in which a possibly imaginaryfocal cone intersects the part of the scan line already covered: This isthe case if no focus effective zones were realized in the cut area or inthe cut areas of the scan line, or if a cut region indeed containsrealized focus effective zones, but the focused radiation remainsshadowed as long as its imaginary focal cone is in the region of focuseffective zones which have already been realized.

This condition is fulfilled in a simple manner when a scan pattern isdesigned such that the focus effective zones, which are located in thebeam path of the radiation furthest from the device for generating theradiation, are first applied: The other focus effective zones are thenrealized successively in the direction of larger z-values, thus towardsthe radiation source. Thus, if a scan pattern shall result in a regionthat is smaller than the section in which the fast scanning movement canbe carried out, the scan pattern may be encoded and realized in thismanner. This is also a solution if a next scan pattern or a next part ofa complex scan pattern shall be created with a distance from said firstscan pattern of the first section, wherein the focal cone of the focusedradiation for the focus effective zones of the scan pattern to berealized in the second section does not comprise already realized focuseffective zones of the scan pattern of the first section, which would bethe case, if the second scan pattern or the second part of a complexscan pattern shall not be set directly subsequent to the first pattern.

If, however, both sections shall be placed next to each other,especially over a wide z-region, perhaps because the processing areashall be continued seamlessly, then some focus effective zones alreadyrealized will be arranged at least in a boundary region in the focalcone of focus effective zones yet to be realized. If these are also tobe avoided, these boundary regions first have to be omitted independence on the size of the focal angle of the focal cone of thefocused radiation and be filled successively at the end.

The system for example, contains a device for changing the position ofthe focus, which comprises a fast z-scanner for fast scanning in adirection parallel to the base position beam axis and at least one fastlateral scanner for fast scanning in a plane vertical to the baseposition beam axis for realizing the fast scanning movement in thesection of the processing volume in addition to a slow z-scanner forslow scanning in a direction parallel to the base position beam axis andat least one slow lateral scanner for slow scanning in a plane verticalto the base position beam axis for realizing the slow scanning movementin the processing volume.

By a cooperation of one or several fast lateral scanners and the fastz-scanner controlled in dependence on a desired direction of the fastscanning movement, a fast scanning movement is possible in an arbitrary,changeable direction in a section of the processing volume.

For the slow scanning movement in the processing volume, a slowz-scanner which is independent of the fast z-scanner and one or moreslow lateral scanners, which are also independent of the respective fastlateral scanners are provided, whose cooperation is also controlled inaccordance with of the desired direction.

In one embodiment of the system, the faster lateral scanner is formed bya fast x-scanner, which is present in addition to a further fast lateralscanner. This further fast lateral scanner is formed by a fasty-scanner. The fast x-scanner and the y-fast scanner can thereby also bepresent in a common x-y-scanning unit. Such an x-y-scanning unit thatactually contains a fast x-scanner and a fast y-scanner can for examplebe realized by a gimbal scanner.

In an alternative embodiment, a fast lateral scanner is formed by a fastR-scanner whose scanning movement can be aligned in an x-y-planevertical to the base position beam axis by rotation about a rotationaxis parallel to the base position beam axis about an angle 1. Therotation itself can be carried out slowly.

Some alternative embodiments are in principle also possible for the slowlateral scanner or scanners.

The slow and the fast lateral scanning can therefore consist of themovements of an x- and a y-scanner, wherein the movements of thex-scanner and the y-scanner are matched to one another such that adesired direction of the scanning movement results in the x-y-plane.Alternatively, the lateral scanning can be carried out in a desireddirection of the scanning movement in the x-y plane by a R scanner,wherein the direction of the scanning movement is controlled in that theR-scanner is aligned by a rotation by an angle 1 about a rotation axisparallel to the base position beam axis.

In a particular embodiment, the system contains a fast z-scanner, whichcomprises a lens element oscillating in the z-direction. Thisoscillating lens element is for example a negative lens, thus a concavelens, which acts, together with a fixed positive lens, thus a convexlens, as a beam widening telescope. In principle, a positive lens, thusa convex lens, can also be selected as the oscillating lens element. Butthen, the position of an intermediate focus must be paid attention to.

In this embodiment, the system further contains a fast two-dimensionallateral scanner, which comprises an x-y-mirror element movable about twoaxes or two individual mirror elements respectively movable about oneaxis, whose axes are for example perpendicular to each other. Byapplication of this fast lateral scanner, a fast movement in the lateralplane is possible, thus the x-y-plane, in particular a fast oscillatingmovement in the x-y-plane.

In this embodiment, the system also contains a slow z-scanner, whichcomprises a lens element optionally movable in the z-direction, againfor example a negative lens, which acts together with a fixed positivelens as beam expansion telescope, and a slow lateral scanner, whichcomprises a focusing optical system optionally displaceable in thelateral plane. The optical system for focusing can thus be displacedlaterally, wherein the directed radiation is directed on this focusingoptical system by mirrors moving along in a fixed relation to thedisplaceable focusing optical system.

In one example embodiment of the system, synchronous changes ofdirection of the fast scanning movement are carried out in at least twospatial directions. This is implemented by the synchronous change ofdirection of at least two fast scanners. The synchronous changes ofdirection of at least two fast scanners are carried out in a definedtemporal relationship to each. For example, they can be carried outsimultaneously. Alternatively, however, a defined temporal offset of thesynchronous changes of direction of at least two faster scanners ispossible.

The fast scanners thus pass along predetermined space-time curves, whichare synchronized with each other. It is not necessarily required thatthese are synchronized to the movement of the slow scanners.

The synchronous changes of direction of the fast scanning movement in atleast two spatial directions can thereby be carried out periodically andcan be carried out by synchronous periodic changes of direction of atleast two fast scanners. The fast scanners in the corresponding spatialdirections thus change their direction temporally coordinated to eachother in a defined period.

In particular, this can be carried out in a simple manner by synchronousoscillatory movements of at least two fast scanners.

A synchronous oscillatory movement of two fast lateral scanners, thus afast x-scanner and a fast y-scanner, enables the processing of an areaperpendicular to the base position beam axis. If this exceeds theachievable section of the processing volume, which can simultaneously beachieved by the fast scanners, a superposition of a slow scanningmovement in the x- and/or y-direction is necessary, in order to processsuch an area. If oscillatory movements of two fast lateral scanners thatare synchronized to each other, are superimposed with a slow scanningmovement, which also contains a z-component, then processing areas asshown in FIG. 2 are possible.

One of these fast scanners can for example be a resonant scanner, theother fast scanners must then be able to be synchronized on its resonantfrequency. That is, that one of at least two fast scanners is then aresonant scanner with a free oscillation, and all others of the at leasttwo fast scanners are synchronized to the resonant scanner. Thissynchronization is advantageously phase-locked.

By using a resonant scanner, it is possible to significantly increasethe scanning frequency, and thus the scanning speed in comparison to apure use of non-resonant scanners, a factor of 5 to 10 is possiblehereby.

Another example is an embodiment in which the fast scanning movement iscarried out by synchronous oscillatory movements of the fast z-scannerand at least one fast lateral scanner, thus a fast x- and/or y-scanner,or the R-scanner.

For example, altogether six-scanners are used in the system according tothe invention. For each spatial direction x, y and z respectively thereis a fast scanner which carries out oscillating movements. This permitsto scan a three-dimensional section of the processing volume of about 1mm×1 mm×1 mm with several hundred Hertz. In addition there is a slowscanner for each spatial direction x, y and z, which permits to achievethe complete necessary processing volume.

For processing of an area in a processing volume, the movement forrealizing a scan pattern along the scan line is assembled from a slowscanning movement and a fast scanning movement by the fast scannerssynchronously oscillating with each other in a system according to theinvention, which can perform a fast scanning movement independently of aslow scanning movement in every arbitrary direction in the processingvolume, and which, for realizing the fast scanning movement of thesynchronous oscillatory movements uses at least two fast scanners, andin particular, the synchronous oscillatory movements of a fast z-scannerand at least one, usually two fast lateral scanners in the form of anx-scanner and a y-scanner.

The slow scanning movement can thereby be performed at a constant speedor at a varying speed in dependence on the location and/or time. It hasa lateral component in the x-direction and/or in the y-direction.

It is the aim to create a scan pattern such that a focus effective zonewhich is already realized is always arranged outside the focal cone of afocus effective zone still to be realized. It is therefore importantthat an oscillating, thus “swinging” scanning movement is performed suchthat minimum z-values are reached when it swings ahead in a slow“feeding direction”. Thus, focus effective zones still to be realizedare always placed above focus effective zones which are alreadyrealized.

The oscillatory movement of the fast z-scanner is therefore synchronizedto the oscillatory movement of a fast lateral scanner or two fastlateral scanners in the form of a fast x- and/or fast y-scanner fast sothat, at a positive lateral component of the slow scanning movement inthe x- and/or y-direction, the oscillatory movements of the fast lateralscanner, in particular of the fast x-scanner and/or the fast y-scanner,are in phase opposition to the oscillatory movement of the fastz-scanner and that with a negative lateral component of the slowscanning movement in the x- and/or y-direction, the oscillatorymovements of the fast lateral scanner, in particular of the fastx-scanner and/or the fast y-scanner, are in phase to the oscillatorymovement of the fast z-scanner

The oscillatory movement of the fast z-scanner between a minimum z-valueand maximum z-value is therefore synchronized to the movement of a fastoscillatory lateral scanner or two fast lateral scanners in the form ofa fast x- and/or a fast y-scanner, which oscillate between a minimumx-value and a maximum x-value and/or a y-minimum value and a maximumy-value.

The amplitude of the oscillatory movement can thereby change temporallyor spatially. The maximum and minimum x-, y- and z-values of theoscillatory movement in a section of the processing volume are thereforenot to be regarded as a constant.

Thereby, at least two oscillatory movements are synchronized to eachother such that—the maximum x-value of the fast lateral scanner occursin the x-direction, thus of the fast x-scanner, and/or the maximumy-value of the fast lateral scanner occurs in the y-direction, thus ofthe fast y-scanner, with a minimum z-value of the fast z-scanner and theminimum x-value of the fast lateral scanner occurs in the x-directionand/or the minimum y-value of the fast lateral scanner occurs in they-direction at a maximum z-value of the fast z-scanner for a lateralcomponent of the slow scanning movement in the positive x- and/ory-direction, and—the minimum x-value of the fast lateral scanner occursin the x-direction and/or the minimum y-value of the fast lateralscanner occurs in the y-direction at a minimum z-value of the fastz-scanner and the maximum x-value of the fast lateral scanner occurs inthe x-direction, and the maximum y-value of the fast lateral scanneroccurs in the y-direction at a maximum z-value of the fast z-scanner fora lateral component of the slow scanning movement in the negative x-and/or y-direction.

Once there is a lateral component of the slow scanning movement ispresent in the same direction, in which an oscillatory movement of afast lateral scanner for the realization of the fast scanning movement,and additionally an oscillatory movement of a fast z-scanner is present,one has to pay attention to the mentioned conditions during thesynchronization of the fast scanners with each other: This enables therealization of a scan pattern such that focus effective zones result oninclined scan lines and focus effective zones already realized arealways arranged outside a focal cone for focus effective zones still tobe realized, the focal cone being formed by the focus of the focusedradiation and the focal angle.

The slow scanning movement can thereby also have a component in thez-direction. Regarding a slow scanning movement in the z-direction, thesynchronization of two fast movements with a periodic change ofdirection, in particular the phase position of the synchronization ofthe oscillatory movement of a fast z-scanner with at least one fastlateral scanner is however not of importance. However, the slow scanningmovement in the z-direction always has to be carried out in the positivedirection, thus parallel to the base position beam axis and against thebeam direction of the radiation.

Furthermore, in an example embodiment a system comprising a controldevice is advantageous, into which a scan pattern is encoded, whichcomprises adjacent strokes. A stroke comprises an essentially straightpart of a scan line, and is realized by a juxtaposition of focuseffective zones of the focused radiation on this part of the scan line.

A stroke thereby does not necessarily describe a straight line:Curvatures or deviations from a straight line of several degrees toseveral ten degrees are possible. The part of the scan line comprised bya stroke is rather aligned in a direction in the processing volume ofthe system, so that it does not comprise any reversing points of thefast scanning movement in the x-, y- and/or z-direction. When the scanline passes a reversing point of the fast scanning movement, a nextstroke results thereafter.

Adjacent strokes have an essentially same distance. The fact that thedistance does not have to remain exactly the same means that thedistance of adjacent strokes can fluctuate by several percent, whereby amaximum distance should not be exceeded, so that the intended effect bythe influence of the focused radiation is not interrupted. Already by achanging curvature or alignment of a stroke compared to the adjacentstroke, an exactly the same distance of the adjacent strokes over theirentire length is often not possible.

The strokes respectively have angles of inclination, wherein the angleof inclination of a stroke is the angle between the stroke and the beamaxis. The angles of inclination of two adjacent strokes are notnecessarily the same, the inclination angle can also change along astroke. For a curved stroke, the decisive angle of inclination is thesmallest angle between a tangent to the curvature line of the stroke andthe beam axis.

However, the scan pattern must be encoded in this embodiment of thesystem according to the invention in such a manner that the respectiveangle of inclination of the stroke to the beam axis is larger or equalto the focal angle of the focused radiation.

The condition that the inclination angle of the stroke to the optic axismust be larger than the focal angle of the focused radiation, therebyapplies for each individual stroke and at any point of the stroke—thelatter condition is important for curved strokes. The condition isfulfilled by the consideration of the smallest angle, as shown above.

Regardless of their angle of inclination, for strokes superposed in thedirection of the beam axis and against the beam direction of theradiation or crossing strokes, a following stroke is always realizedover the adjacent preceding stroke, so that the condition that focuseffective zones already realized are always arranged outside of a focalcone for focus effective zones still to be realized, is fulfilled.

If the strokes are generated by the superposition of a slow and a fastscanning movement, wherein the fast scanning movement is realized bysynchronous oscillatory movements of a fast z-scanner and at least afast lateral scanner, then the mentioned conditions regarding minimumand maximum values for the synchronization have to be noted; thenecessary angle of inclination can be generated by a corresponding ratioof slow and fast scanning movement.

In a variant of a system according to the invention, the control deviceis thus encoded such that the formation of a stroke is always realizedby stringing together focus effective zones of focused radiation only inan upward movement along the scan line or only in a downward movementalong the scan line: An upward movement is thereby a movement with az-component against the beam direction, while a downward movement is amovement with a z-component in the direction of the beam direction.

If the strokes are generated by a synchronous oscillatory movement of afast z-scanner and at least one fast lateral scanner, focus effectivezones are always set only in a half period of the oscillatory movement.When the slow scanning movement superimposed over the fast scanningmovement is constant, this results in regularly arranged strokes. Whenthe lateral component of the slow scanning movement is identical to thedirection of the oscillatory movement of the at least one lateralscanner, the strokes always have the same distance to each other.

By using the downward movement, it is advantageous if the angle ofinclination of the strokes to the beam axis is larger than the focalangle of the focused radiation, so that a focus effective zone alreadyrealized is also not arranged on the cone area of the focal cone of afocus effective zone still to be realized.

In another variant of a system according to the invention, the controldevice is encoded so that the formation of the strokes is realizedalternately through stringing together focus effective zones of focusedradiation in a upward movement and a downward movement along the scanline. Thereby strokes result with essentially two different angles ofinclination, but advantageously focus effective zones can be realizedhere during the entire period of the oscillatory movement.

In one embodiment of the system according to the invention, the devicefor generating radiation comprises a pulsed laser with a laser pulserepetition rate. A distance of a focus effective zone of a precedingfocus effective zone is then given by the laser pulse repetition rateand an overall scanning speed, which is composed of the scanning speedsof slow and fast scanning movements.

The scanning speeds are thereby not necessarily constant. In particularfor the oscillatory movement, the speed is the highest at a zerotransition of the oscillation, and the lowest at the reversal point,thus at the minimum value and at the maximum value of the oscillatorymovement.

It is then of particular advantage if the control device is adapted tomask a laser pulse, when its focus effective zone falls below a minimumdistance to the preceding focus effective zone. Damages in thetransparent material to be processed can thereby be avoided, which canoccur when several focus effective zones are realized at the sameposition or at positions close to each other in the processing volume.

In this example embodiment of the system according to the invention,several advantageous characteristics are thus combined, which mutuallyinfluence each other positively in order to process a processing areaprecisely and with a high quality with a focused radiation, withoutcausing damage.

By stringing strokes together, which have an angle of inclination to theoptical axis, which is larger than the focal angle on the one hand, thuslarge enough that existing focus effective zones from the part of thescan pattern already realized are penetrated by the focused radiationonly in areas behind the focal point of the focused radiation, there isno shadowing. When the strokes on the other hand have an angle ofinclination which is smaller than 90°, area shapes can be generatedthereby which have no border regions, or for the special case of closedareas, at maximum have a border region to already completed focuseffective zones. By masking laser pulses in dependence on the speed ofthe overall scanning movement composed of the fast and slow scanningmovement damage in the transparent material to be processed, especiallydamage in an ocular tissue, is avoided. In addition, a processing of anarea with such a scan pattern leads to an efficient filling of theprocessing area. In case of an incision area generated by the focuseffective zones of a pulsed laser, for example a femtosecond laser, thisleads to a clean cut area, in which the risk of tears is minimized.

A system according to the invention thus allows the effective,time-saving arrangement of focus effective zones, in particular of laserfocus effective zones, in a scan pattern which takes into accountcharacteristics of the device for change of the position of the focus,in particular of a scanning system comprised herein, to only havequickly accessible a section of the three-dimensional processing volume,but to be able to move this section slowly through the entire processingvolume. The latter allows the use of an cheap focusing optical systemwith a small field and the restricted width of a fast focus depthadjustment.

If, due to only a small extent of the processed area, a small,cost-efficient optical system is sufficient, without the latter havingto be then moved, or if the achieved speed of processing is not relevanteven in extensive areas to be treated, then the system for processing anarea in a processing volume of a transparent material by application ofa focused radiation, in particular an ophthalmologic therapy device,comprising a device for generating a radiation and an optical system forfocusing the radiation into a focus in the processing volume, whereinthe focus of the focused radiation has a focal angle and the focusedradiation has a beam axis according to the above given definitions. Thedevice for producing a focusable radiation may comprise a laser,preferably a pulsed laser and in particular a short pulse laser such asa picosecond or femtosecond laser having the characteristics describedabove.

The system further includes a device for changing the position of thefocus of the focused radiation by a scanning movement in an arbitrarilychangeable processing volume, wherein the processing volume and thus thescanning movement and a scan pattern resulting from it is determined bythree spatial directions x, y and z. Herein, the x-direction and they-direction are non-parallel to each other and respectively normal to abase position beam axis and the z-direction is parallel to the baseposition-beam axis, which denotes the beam axis of the focused radiationwithout deflection of the focus through the device for changing theposition of the focus in the processing volume in the two lateraldirections x and y. Changing the position of the focus is for examplecarried out continuously, but not necessarily at a constant speed. Forthis purpose, the device for changing the position of the focus maycomprise three mutually independent scanners, for example an x-scanner,y-scanner and a z-scanner. These scanners may also be characterized asto the achievable processing volume and speeds by the values mentionedabove. Also, the slow x-scanner can be combined with the slow y-scannerin an x-y scanning unit.

The system is characterized by a control device which is adapted tocontrol the system, in particular for controlling the device forgenerating a radiation, the device for changing the position of thefocus of the focused radiation and/or the optical system. For thatpurpose it is connected to the device for generating a radiation, thedevice for changing the position of the focus of the focused radiationand/or the optical system via appropriate communication paths.

The control device may again be designed in one piece or in severalparts. According to an example embodiment of the invention, a scanpattern is encoded into the control device, which can be realized by thescanning movement along a scan line, said scanning movement comprisingat least one lateral base component in the x- and/or y-direction. Thescanning movement can also further comprise a base component in thez-direction.

However, the scanning movement is not characterized by an constantmovement in an arbitrary direction: rather, a lateral base component inthe x- and/or y-direction and optionally also a base component in thez-direction is superimposed by components of synchronouschange-of-direction-movements in the z-direction and in at least one ofthe lateral spatial directions x- and/or y. The synchronouschange-of-direction-movements are therefore portions of an overallmovement in a corresponding direction, which are composed of therespective base component and the respectivechange-of-direction-movements in this direction.

The synchronous change-of-direction-movements in the z-direction and inat least one of the lateral spatial directions x- and/or y can therebybe carried out in a defined temporal relationship to each other. Inparticular, the changes of direction can occur simultaneously.Alternatively, however, a defined temporal offset of the synchronouschanges of direction is possible.

The synchronous change-of-direction-movements in the z-direction and inat least one of the lateral directions in space x- and/or y can beeffected periodically.

The lateral base component in the x- and/or y-direction is superimposedby the synchronous change-of-direction-movements in the z-direction andin x-direction and/or in the y-direction, which are synchronized witheach other such that, for a positive lateral base component of thescanning movement in x- and/or y-direction, thechange-of-direction-movements in the x- and/or y-direction are in phaseopposition to the change-of-direction-movements in the z-direction, andthat at a negative lateral base component of the scanning movement inthe x- and/or y-direction, the periodic change-of-direction-movements inthe x- and/or y-direction are in phase to the periodicchange-of-direction-movements in the z-direction.

A lateral base component invariantly directed in the x- and/ory-direction and optionally also a base component invariantly directed inthe z-direction is thus superimposed to thechange-of-direction-movements in the z-direction between a minimumz-reversal point and a maximum z-reversal point, which are synchronizedto change-of-direction-movements in at least one lateral spatialdirection x- and/or y between a minimum x-reversal point and a maximumx-reversal point and/or between a minimum y-reversal point and a maximumy-reversal point. The value of the respective x-, y- or z-reversal pointis generally not a constant but may be varied within the possibilitiesof the processing volume.

In this case, at least two change-of-direction-movements aresynchronized to each other such that the maximum x-reversal point and/orthe maximum y-reversal point correspond to a minimum z-reversal pointand the minimum x-reversal point and/or the minimum y-reversal pointcorrespond to a maximum z-reversal point for a lateral base component inthe positive x- and/or y-direction and the minimum x-reversal pointand/or the minimum y-reversal point correspond to a minimum z-reversalpoint and the maximum x-reversal point and/or the maximum y-reversalcorrespond to a maximum z-reversal point for a lateral base component inthe negative x- and/or y-direction.

However, the resulting scanning movement is not the result of theinteraction of several scanning movements which are generated bydifferent scanning systems or with different scanners, but it isrealized by one scanning system, for example using one scanner for eachof the spatial directions x, y and z, which are part of the device forchanging the position of the focus in the processing volume.

When there is a lateral base component invariantly directed in the samedirection, in which the change-of-direction-movements are carried out,and additionally change-of-direction-movements are carried out in thez-direction, the mentioned conditions have to be considered whensynchronizing the change-of-direction-movements among each other: Thisallows to realize a scan pattern such that focus effective zones oninclined scan lines result, during whose generation as few as possibleshadowing effects are effective by structures of the already processedregions of the processing area.

Such a proceeding, which is locally very limited at every moment is forexample favorable in eye surgery in order to minimize the impact of apossible movement of the eye during the surgery. In contrast to theprior art, with the system according to the invention—as well as acorresponding process—the entire processing volume is not processed overa long period, and always only a small part of an incision plane iscompleted, which otherwise would lead to an offset within an incisionplane during movements of the eye, the incision plane then beingpossibly not completely carried out. With the system according to theinvention and the corresponding method on the other hand, the incisionis immediately completed locally.

By a corresponding selection of the invariantly directed lateral basecomponent in the x- and/or y-direction and the speed and the “amplitude”of the change-of-direction-movements in the respective lateral spatialdirection x- and/or y and their implementation by encoding into thecontrol device, a scan pattern is encoded in an example system accordingto the invention, which has a sequence of focus effective zones of thefocused radiation along a scan line, such that focus effective zonesalready realized are always arranged outside of a focal cone, which isformed by the focus of the focused radiation and the focal angle, forfocus effective zones still to be realized, as the inclination of thescan lines to the beam axis can be determined hereby.

Another example is a system in whose control device a scan pattern isencoded which has mutually adjacent strokes with inclination angles tothe beam axis, wherein a stroke comprises a straight section of the scanline and is realized through stringing together focus effective zones offocused radiation, and wherein the angles of inclination of the strokesare larger or equal to the focal angle of the focused radiation. Withsuch a scan pattern, a sequence of the arrangement of the focuseffective zones is accomplished such that focus effective zones alreadyrealized are always arranged outside a focal cone which is formed by thefocus of the focused radiation and the focal angle for focus effectivezone which are still to be realized.

For an arrangement of strokes with an inclination angle to the beam axisa subsequent stroke is thus realized above the adjacent stroke, whereby“above” means an arrangement in a direction opposite to the beamdirection.

The control device can be encoded such that the formation of the strokesby stringing together focus effective zones of focused radiation isalways in an upward movement, or always in a downward movement orrealized alternately in an upward movement and a downward movement alongthe scan line.

The device for generating a radiation of a system according to anexample embodiment of the invention may comprise a pulsed laser with alaser pulse repetition rate, wherein a distance of a focal effectivezone from a preceding focus effective zone is determined by the laserpulse repetition rate and a scanning speed. Then it is advantageous ifthe control device is set up to mask a laser pulse, when its focuseffective zone falls below a minimum distance to the preceding focuseffective zone.

Processing an area in very high quality also requires reducing orideally avoiding completely damages to the processed transparentmaterial. A system for processing an area in a processing volume of atransparent material by application of a focused radiation, inparticular an ophthalmologic therapy system, comprises a device forgenerating a radiation that comprises a pulsed laser with a laser pulserepetition rate, and an optical system for focusing the radiation into afocus in the processing volume, a device for changing the position ofthe focus of the radiation focused in the processing volume, and acontrol device adapted to control the system.

Again, the device for generating a radiation can comprise a pulsedlaser, in particular a short pulse laser such as a picosecond orfemtosecond laser having the characteristics described above. The devicefor changing the position of the focus can include a scanning systemwith an x-scanner, a y-scanner and a z-scanner. These can becharacterized with respect to the achievable processing volume andspeeds by the above mentioned values.

In such a device, a distance of a focal effective zone from a precedingfocus effective zone is determined by the laser pulse repetition rateand a scanning speed that can vary spatially and temporally. The controldevice of the system according to the invention is arranged to avoiddamages of the transparent material to be processed, by masking a laserpulse, if a distance of the focus effective zone of the laser pulse tothe preceding focus effective zone is below a minimum distance.

This is particularly the case with oscillating scanning movements, inwhich there are respectively reversal points at which the speed of thecorresponding scanning movement in the direction in question approacheszero. It is useful, for example, with oscillations in the z-direction,to mask the laser pulses in a region around the upper and the lowerreversal point, thereby avoiding closely spaced focus effective zones,or even more to avoid focus effective zones on identical locations.

A method for processing an area in a processing volume of a transparentmaterial, in particular an eye, by a focused radiation by application ofa system, which comprises a device for generating a radiation and anoptical system for focusing the radiation into a focus in the processingvolume, which can be described with three spatial directions, x, y andz, is characterized in that the position of the focus of the thusfocused radiation is changed by a slow scanning movement in theprocessing volume of the transparent material and a fast scanningmovement in a section of the processing volume in any, by the threespatial directions determined direction. The section of the fastscanning movement is, however, moved by the slow scanning movement inthe entire processing volume. The z-direction is parallel to the basesetting beam axis.

Both the slow and the fast scanning movement is thus possible in anarbitrary direction in the processing volume. The fast scanning movementis carried out with a maximum speed, which is a multiple of the maximumspeed of the slow scanning movement.

Here, the focus has a focal angle, which characterizes the opening angleof the focus and describes the angle between a straight line extendingin the cone surface of the focal cone and a beam axis of the focusedradiation.

Preferably in a method according to the invention, a scan pattern isrealized in the transparent material by generating a sequence of focuseffective zones of the focused radiation along a scan line in such a waythat already realized focus effective zones are always arranged outsidea focal cone, which is formed by the focus of the focused radiation andthe focal angle, for focus effective zones still to be realized

It is advantageous according to example embodiments, if in a methodaccording to the invention for processing an area in a processing volumeof a transparent material synchronous changes of direction of the fastscanning movement are carried out in at least two directions in space:This allows processing of a section of the processing volume quickly andeffectively, while this section can be moved through the entireprocessing volume by application of the slow scanning movement.

The synchronous changes of direction thereby are carried out in adefined temporal relationship to each other. In particular, they can becarried out simultaneously. Alternatively, however, a defined temporaloffset of the synchronous changes of direction of the fast scanningmovement in at least two directions in space is possible.

The synchronous changes of direction of the fast scanning movement in atleast two spatial directions can also be carried out periodically.

For example, such a fast scanning movement is carried out by synchronousoscillatory movements in at least two directions in space. By using afast oscillating scanner for each of the spatial directions x, y and zthe oscillatory movements of the fast z-scanner are thereforesynchronized with those of fast x-scanner and/or the fast y-scanner.

If a fast z-scanner is used in conjunction with a fast R-scanner, whichcan be rotated about the optical axis, the fast z-scanner issynchronized with the fast R-scanner.

Hereby one of these fast scanners can be a resonant scanner, the otherfast scanners must then be able to be synchronized on that resonantfrequency.

In particular, according to example embodiments, it is advantageous forthe method according to the invention when the fast scanning movement iscarried out by synchronous oscillatory movements in the z-direction andin at least one of both lateral spatial directions x and y.

It is particularly advantageous, for example, if a method, in which aslow scanning movement is carried out with a lateral component in thex-direction and/or in y-direction, and the fast oscillatory movements inthe z-direction and in x-direction and/or y-direction are synchronizedto each other such that, for a positive lateral component of the slowscanning movement in the x- and/or y-direction, the fast oscillatorymovements in the x-direction and/or y-direction occur in phaseopposition to the oscillatory movement in the z-direction, and that, fora negative lateral component of the slow scanning movement in x- and/ory-direction, the fast oscillatory movements in the x-direction and/ory-direction occur in phase with the oscillatory movement in thez-direction.

In such a method according to an example embodiment of the invention,therefore, the fast oscillatory movement between a minimum z-value andmaximum z-value for the fast oscillatory movement between a minimumx-value and a maximum x-value and/or a minimum y-value and a maximumy-value are synchronized such that

-   -   the maximum x-value and/or the maximum y-value is achieved at a        minimum z-value and the minimum value of x- and/or the minimum        y-value is achieved at a maximum z-value for a lateral component        of the slow scanning movement in positive x- and/or y-direction,        and    -   the minimum x-value and/or the minimum y-value is achieved at a        minimum z-value and the maximum x-value and the maximum y-value        is achieved at a maximum z-value for a lateral component of the        slow scanning movement in negative x- and/or y-direction.

The amplitude of the oscillatory movement can thereby change temporallyor spatially.

In an advantageous embodiment of the method according to an exampleembodiment of the invention, a scan pattern is generated, which hasmutually adjacent strokes with inclination angles to the beam axis,wherein a stroke comprising a straight section of a scan line and isimplemented by a series of focus effective zones of focused radiation,wherein the inclination angle of the strokes to the beam axis is largeror equal to the focal angle of the focused radiation.

The inclination angle of the stroke to the beam axis can vary in thiscase, but it may never be less than the focal angle of the focusedradiation.

The latter condition must always apply, that is, for each stroke at anypoint of the stroke, to guarantee that realized focus effective zones ofadjacent strokes already realized are not located in the focal cone of afocus effective zone still to be realized. In compliance with thiscondition, a stroke to be realized thereby respectively is carried outabove the adjacent stroke already realized, thus in compared to theprevious stroke, in the positive z-direction.

The strokes may be formed in an alternative embodiment of the methodaccording to the invention in that focus effective zones of the focusedradiation are always lined up in an upward movement, or always in adownward movement along the scan line. In another alternative, thestrokes can alternately be aligned in an upward movement and a downwardmovement along the scan line.

The scanning movements are not necessarily carried out at a constantspeed. In particular for oscillatory movements, the speed of thescanning movement is the highest at the zero transition of theoscillation, and lowest at the reversal point, that is the maximum valueor minimum value of the oscillatory movement. Also the slow scanningmovement can be carried out as a movement with an adjustable speed.

In an advantageous embodiment of the method according to the invention,the device for generating a radiation generates a pulsed laser radiationwith a laser pulse repetition rate. The distance of a focal effectivezone from a preceding focus effective zone is determined by the laserpulse repetition rate and an overall scanning speed, which is composedof the scanning speeds of the slow and fast scanning movements.

If a distance of a focus effective zone now falls below a specifiedminimum distance to the preceding focus effective zone, the laser pulseis masked and the focus effective zone is not realized. This minimumdistance is determined such that a repeated input of energy by two ormore successive laser pulses at the focal point in a processedtransparent material in close proximity to the preceding energy input,or even in the same place, is avoided, and it therefore does not resultin unwanted changes of the material. Damages in the material willtherefore be avoided.

Procedurally, the embodiments of the invention allow for areas to beprocessed having a low expansion or without any demands on the speed ofprocessing by a method for processing a surface in a processing volumeof a transparent material, in particular an eye, by a focused radiationby application of a system comprising a device for generating radiationand an optical system for focusing the radiation into a focus in theprocessing volume, which is determined by three spatial directions x, yand z, wherein the position of the focus of the thus focused radiationis changeable by a scanning movement in the processing volume of thetransparent material in any arbitrary direction, determined by the threespatial directions x, y and z, and wherein a scan pattern is generatedin the transparent material along a scan line by the action of thefocused radiation during the scanning movement. Therein, the z-directionis arranged parallel to a base position beam axis.

According to the invention, a scanning movement is carried out therebyhaving at least a lateral base component in the x- and/or y-direction.The scanning movement can further also comprise a base component in thez-direction. For determining this scanning movement, the lateral basecomponent is superimposed in the x- and/or y-direction and possibly alsothe base component in the z-direction is superimposed by components ofsynchronous changes of direction movements in the z-direction and in atleast one lateral spatial direction x- and/or y, wherein thechange-of-direction-movements are synchronized to each other such that,with a positive lateral base component of the scanning movement in thex- and/or y-direction, the change-of-direction-movements are carried outin the x- and/or y-direction opposite to thechange-of-direction-movements in the z-direction, and that, with anegative lateral base component of the scanning movement in the x-and/or y-direction, the change-of-direction-movements in the x- and/ory-direction are carried out in the same direction as thechange-of-direction-movements in the z-direction.

The synchronous change-of-direction-movements thereby are carried out inthe z-direction and in at least one of the lateral spatial directions x-and/or y in a defined temporal relation to each other. In particular,the changes of direction movements can occur simultaneously.Alternatively, however, a defined temporal offset of the synchronouschanges of direction is possible.

The synchronous change-of-direction-movements in the z-direction and inat least one of the lateral spatial directions x- and/or y can also becarried out periodically.

An invariably directed lateral base component in the x- and/ory-direction and optionally also an invariably directed base component inthe z-direction is thus superimposed to thechange-of-direction-movements in the z-direction between a minimumz-reversal point and a maximum z-reversal point, which are synchronizedto the change-of-direction-movements in at least one lateral spatialdirection x- and/or y between a minimum x-reversal point and a maximumx-reversal point, and/or between a minimum y-reversal point and amaximum y-reversal point.

These changes of direction movements being carried out in at least twospatial directions are synchronized to each other such that the maximumx-reversal point and/or the maximum y-reversal point is achieved at aminimum z-reversal point and the minimum x-reversal point and/or theminimum y-reversal point is achieved at a maximum z-reversal point for alateral base component in positive x- and/or y-direction and the minimumx-reversal point and/or the minimum y-reversal point is achieved at aminimum z-reversal point and the maximum x-reversal point and/or themaximum y reversal point is achieved at a maximum z-reversal point for alateral base component in negative x- and/or y-direction.

The scanning movement is realized by a scanning system, for exampleusing a scanner for each of the spatial directions x, y and z.

In an advantageous example embodiment of the method according to theinvention, a scan pattern is generated by a series of focus effectivezones of the radiation focused along a scan line in the transparentmaterial. This scan line is thereby controlled such that focus effectivezones already realized are always arranged outside a focal cone forfocus effective zones still to be realized. The focal cone is determinedby the focus of the focused radiation and the focal angle, whichdescribes the angle between a straight line extending along the conesurface and focus the beam axis.

In an advantageous example embodiment of the method according to theinvention, a scan pattern is generated, which has mutually adjacentstrokes with inclination angles to the beam axis, wherein a strokecomprises a straight part of a scan line and is realized by stringingtogether focus effective zones of focused radiation, and wherein theinclined angle of the strokes to the beam axis is larger or equal to thefocal angle of the focused radiation.

A stroke can be formed in that focus effective zones of the focusedradiation are always lined up in an upward movement, or always in adownward movement along the scan line. Alternatively, a stroke can beformed in that focus effective zones of the focused radiation arealternately lined up in an upward movement and downward movement alongthe scan line.

Another method according to the invention for processing an area in aprocessing volume of a transparent material by a focused radiation iseffected by application of a system which comprises a device forgenerating a radiation, in which a pulsed laser radiation is generatedwith a laser pulse repetition rate, and an optical system for focusingthe radiation at a focal point in the processing volume, wherein theposition of the focus of the focused radiation is changed by a scanningmovement in the processing volume of the transparent material. Adistance of a focal effective zone from a preceding focus effective zoneis determined in this process by the laser pulse repetition rate and ascan speed, and a laser pulse is then masked when the distance of thefocus effective zone from the preceding focus effective zone falls belowa minimum distance. Embodiments of the invention furthermore include acontrol program product, i.e., a computer program product that can beused to control a system.

The control program product according to the invention is configured forencoding a control device of a system for processing of an area in aprocessing volume of a transparent material by application of a focusedradiation.

In particular, in one example embodiment variant, such a control programproduct provides an encoding of a scan pattern in such a manner that itis composed by fast scanning movements in a section of the processingvolume and slow scanning movements in the processing volume in anarbitrary direction determined by three spatial directions, wherein thesection of the fast scanning movement can be moved by the slow scanningmovement in the entire processing volume.

For realizing the fast scanning movement, a scan pattern can be encodedin an example embodiment of the control program product according to theinvention such that synchronous change-of-direction-movements of thefast scanning movement are carried out in at least two spatialdirections, in particular, that a fast scanning movement is generated bysynchronous oscillatory movements of at least two fast scanners, whereinsynchronous oscillatory movements of the fast z-scanner and at least onefast lateral scanner being advantageous.

A control program product for encoding a fast scanning movement by thesynchronized oscillatory movements of the fast z-scanner between aminimum z-value and a maximum z-value and a fast lateral scanner or twofast lateral scanners in the form of a fast x- and/or fast y-scanner,which oscillate between a minimum x-value and a maximum x-value and/or aminimum y-value and a maximum y-value, is for example advantageous. Theat least two oscillatory movements are synchronized with one anothersuch that the maximum x-value of the fast x-scanner, and/or the maximumy-value of the fast y-scanner is achieved with a minimum z-value of thefast z-scanner, and the minimum x-value of the fast x-scanner and/or theminimum y-value of the fast y-scanner is achieved with a minimum z-valueof the fast z-scanner for a lateral component of the slow scanningmovement in the positive x- and/or y-direction; and the minimum x-valueof the fast x-scanner, and/or the minimum y-value of the fast y-scanneris achieved with a minimum z-value of the fast z-Scanner, and themaximum x-value of the fast x-scanner and/or the maximum y-value of thefast y-scanner is achieved with a maximum z-value of the fast z-scannerfor a lateral component of the slow scanning movement in the negative x-and/or y-direction.

For realizing the scanning movement, in a more general, exampleembodiment of control program product according to the invention, a scanpattern can be encoded such that a scanning movement with a lateral basecomponent in the x-direction and/or in the y-direction, if necessaryalso with an additional base component in the z-direction, whichdetermines a base movement, which for example provides a invariablydirected movement, is superimposed with synchronouschange-of-direction-movements in the z-direction and in the x-directionand/or y-direction, which are synchronized to each other such that, witha positive lateral base component of the scanning movement in the x-and/or y-direction, the change-of-direction-movements in the x- and/ory-direction are carried out in the opposite direction to thechanges-of-direction-movements in the z-direction, and that, with anegative lateral base component of the scanning movement in the x-and/or y-direction, the change-of-direction-movements in the x- and/ory-direction are carried out in line with thechange-of-direction-movements in the z-direction.

In a control program product according to the invention, a scan programproduct is preferably encoded in a manner that it has a sequence offocus effective zones of focused radiation along a scan line, such thatfocus effective zones already realized are always arranged outside afocal cone, which is formed by the focus of the focused radiation andthe focal angle for a scan pattern still to be realized.

A particularly preferred control program product according to theinvention comprises the encoding of a scan pattern of mutually adjacentstrokes with inclination angles to a beam axis of the focused radiation,wherein a stroke includes a straight section of a scan line, and isrealized by a series of focus effective zones of the focused radiation,and wherein the angle of inclination of the strokes to the beam axis isequal or larger to the focal angle of focused radiation.

A scan pattern can further be encoded by a control program product insuch a manner that the formation of a stroke by stringing together focuseffective zones of the focused radiation is always realized in an upwardmovement or is always realized in a downward movement along the scanline, or that the formation of the strokes is realized through stringingtogether focus effective zones of focused radiation alternately inupward movement and downward movement.

An example embodiment of the control program product according to theinvention for a system which comprises a device for generating radiationin the form of a pulsed laser radiation with a laser pulse repetitionrate comprises an encoding of a scan pattern such that a laser pulse ismasked when the distance of its focus effective zone to the precedingfocus effective zone falls below a minimum distance.

The above summary is not intended to describe each illustratedembodiment or every implementation of the subject matter hereof. Thefigures and the detailed description that follow more particularlyexemplify various embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

Subject matter hereof may be more completely understood in considerationof the following detailed description of various embodiments inconnection with the accompanying figures, in which the present inventionshall now be explained by use of example embodiments. It is shown in:

FIGS. 1a and 1b is the realization of two incision areas in a processingvolume of a transparent material by application of an optical radiationaccording to the prior art as described above.

FIG. 2 is the realization of an incision area in a processing volume ofa transparent material by lateral wobbling as described above.

FIG. 3 is a first example of a system for processing an area in aprocessing volume of a transparent material by application of a focusedradiation.

FIG. 4 is a scheme of the entire optical structure of an ophthalmologictherapy system according to the invention with an optical system forfocusing a radiation and a device for changing the position of the focusof the radiation,

FIG. 5 is a z-scan module of a fast and slow scanner.

FIG. 6 is the change of divergence during the movement of the focus inthe z-direction.

FIG. 7 is the structuring of a scan pattern for an area to be processedin a processing volume.

FIGS. 8a to 8c is the position of the focal cone of a focus effectivezone to be realized to focus effective zones that are already realizedfor different scan patterns.

FIG. 9 is the advantageous juxtaposition of inclined scan lines forprocessing a closed, cylindrical area.

FIG. 10 is the superposition of a sinusoidal oscillation of the fastz-scanner with a synchronous sinusoidal oscillation of a fast lateralscanner with slow change of the oscillation center point in the positivex-direction for generating straight strokes.

FIG. 11 is the superposition of a sinusoidal oscillation of the fastz-scanner with a synchronous sinusoidal oscillation of a fast lateralscanner with slow change of the oscillation center point in the negativex-direction for the bidirectional generation of strokes.

FIG. 12 is a first scan pattern for generating a capsulotomy incision.

FIG. 13 is a second scan pattern for generating a capsulotomy incision.

FIG. 14 is a third scan pattern for generating a capsulotomy incision.

FIGS. 15a to 15c are different phases of a scan pattern for generating alens fragmentation incision.

FIGS. 15d and 15e are an advantageous scan pattern with crossed incisionplanes.

FIGS. 16a to 16c are a scan pattern for generating an arcuate incisionin different views.

FIGS. 17a to 17c are a first scan pattern for generating an accessincision in different phases.

FIGS. 18a to 18c are a second scan pattern for generating an accessincision in different phases.

FIG. 19 is a second example of a system for processing an area in aprocessing volume of a transparent material by application of a focusedradiation.

While various embodiments are amenable to various modifications andalternative forms, specifics thereof have been shown by way of examplein the drawings and will be described in detail. It should beunderstood, however, that the intention is not to limit the claimedinventions to the particular embodiments described. On the contrary, theintention is to cover all modifications, equivalents, and alternativesfalling within the spirit and scope of the subject matter as defined bythe claims.

DETAILED DESCRIPTION

FIG. 3 shows a first example of an ophthalmologic therapy system forprocessing an area in a processing volume of a transparent material byapplication of a focused radiation.

The system comprises a device for generating a radiation 100 comprisinga femtosecond laser with a wavelength in the range of 1020-1060 nm. Thepulse duration of this femtosecond laser is 500-600 fs, the pulse energyabout 100 and the laser pulse repetition rate about 100 kHz. Inaddition, the system comprises an optical system 2, 200 for focusing theradiation in a focus 4, with a numerical aperture of 0.2, which has afield of view of about 1 mm.

The system also includes a device for changing the position of thefocused radiation. This device can carry out, in any arbitrary directiondetermined by the three spatial directions, a slow scanning movement inthe processing volume 300 of the transparent material 3, here the eye,and a fast scanning movement, which is independent of the slow scanningmovement, in a section 600 of the processing volume 300, wherein thesection 600 of the fast scanning movement can be moved by the slowscanning movement in the entire processing volume 300.

Altogether six-scanners are used. For each of the spatial direction x, yand z, where the z-direction extends parallel to the initial baseposition beam axis 120 and the x- and y-direction extend vertical to thebase position beam axis 120, there is respectively a fast scanner 401,402, 403, which allows to scan a section 600 of about 1 mm×1 mm×1 mm ofthe three-dimensional processing volume 300 with several hundred Hertz.In addition there is a slow scanner 411, 412, 413 for each spatialdirection. These allow the complete necessary processing volumes 600 ofabout 15 mm×15 mm×15 mm for the generation of incisions in an eye tissue3.

The overall implemented scanning movement at a time t is composed ofslowly changeable components in the x-, y- and z-direction, which areidentified by the index s, and rapidly changeable components in the x-,y- and z-direction, which are identified by the index f:

$\begin{pmatrix}{x(t)} \\{y(t)} \\{z(t)}\end{pmatrix} = {\begin{pmatrix}{x_{s}(t)} \\{y_{s}(t)} \\{z_{s}(t)}\end{pmatrix} + {\begin{pmatrix}{x_{f}(t)} \\{y_{f}(t)} \\{z_{f}(t)}\end{pmatrix}.}}$

The slowly changeable components (x_(s), y_(x), z_(s)) can show anarbitrary time behavior and must only remain below a maximum speedv_(max)- and/or a maximum acceleration a_(max).

$\mspace{79mu}{{\frac{d\;{x(t)}}{d\; t} \leq v_{\max}};{\text{?}a_{\max}\mspace{14mu}{\left( {{dito}\mspace{14mu} f\overset{¨}{u}r\mspace{14mu}{y(t)}\mspace{14mu}{und}\mspace{11mu}{z(t)}} \right).\text{?}}\text{indicates text missing or illegible when filed}}}$

The rapidly changeable components (x_(f), y_(f), z_(f)) are not subjectto these restrictions. However, for the area filling, recurring similarmovement paths have to be passed, and the strokes 7 are generatedtherewith. An example of recurring similar movement paths, which shallnot be restricting at this point, would be an oscillation with a periodT:

$x_{f} = {{{X(t)}{\sin\left( {2\;\pi\frac{t}{T}} \right)}} + {{O(t)}.}}$

The amplitude X and a center position O may thereby slowly change withtime, too, similar to the slow components of the scanning movement. Itis only necessary that recurring similar movement paths, thus thetraversed locus curves, are similar. That these will always pass throughin similar times, is not mandatory but a typical realization. Inconjunction with the slow movement, similar strokes 7 are then placedclose together and form an incision area 11.

The system further comprises a one-piece central control system 500,which is connected via the communication paths 501 to the device forgenerating a radiation 100, thus the femtosecond laser system, and tothe device for changing the position 400 of the focus 4, and which isadapted to control the femtosecond laser system and all scanners 401,402, 403, 411, 412, 413 of the device for changing the position 400 ofthe focus 4.

In this example, the laser pulse repetition rate is 100 kHz. Neighboringfocus effective zones shall have a distance of about 10 μm. The scanningspeed of the fast scanners is about 1000 mm/s. With a size of about 1mm×1 mm×1 mm of the section 600 of the processing volume 300 for thefast scanners 401, 402, 403, 100 pulses in 1 ms are resulting.Thereafter, the slow scanning movement should also have achieved aprogression of about 10 μm in the corresponding direction. The slowscanners 411, 412, 413 thus have a scanning speed of about 10 mm/s. Thisresults in a ratio of faster to slower scanning movement ofapproximately 100:1.

This system is used for the generation of incisions by photo disruptionby application of the femtosecond laser. With this system, for example,access incisions of a lateral size of 2 mm, a capsulotomy with a lateraldiameter of 5 mm or relaxation incisions in the cornea over a lateraldiameter of 11 mm can be carried out. In the depth, thus in thez-direction, for simple incisions, where a certain inclined positionshall be considered, an incision depth of 500 pm can be generated, alens thickness of 3-5 mm can be penetrated, or other incisions in thecornea or the lens of 10 to 12 mm depth can be carried out.

FIG. 4 shows a scheme of the entire optical structure of anophthalmologic therapy system with a focusing optical system 200 forfocusing a radiation 1 and a device for changing the position of thefocus of the radiation. This can for example be used in the firstexample of the ophthalmologic therapy system of FIG. 3.

A z-scan module 1400, 401, 411 generates, from the input beam 1401 withconstant divergence, constant deflection and constant diameter, a beamwith modulated divergence, but still constant deflection and constantdiameter in the exit pupil 1403.

A fast x/y-scanner 402, 403—a so-called partial field scanner 1500—whichcan be swiveled about two perpendicular axes and thereby carry outoscillating movements about a zero point about both axes, additionallyimplies a lateral deflection upon the divergence-modulated beam 1402,which creates a deflected divergence-modulated beam 1502 from thenon-deflected, divergence-modulated beam 1501.

The pupil plane 1403, in which the beam diameter is constant, is imagedfrom the relay 1600 into the entrance pupil 1601 of the focusing opticalsystem 200, so that the beam at that point shows a constant diameter buta divergence- and deflection modulation. The focused beam thus has anapproximately constant numerical aperture NA, which is independent ofthe divergence, thus the z-position of the focus 4 and the deflection,thus the x-y-position of the focus 4.

The lateral partial scan field 1800 of the fast x/y scanner, thus thex-y-extension of the section 600 of the fast scanning movement, canadditionally be moved by an optional lateral displacement of thefocusing optical system 200. The tracking of the beam with the movementof the focusing optical system 200 is effected by the mirrors 1701 and1702, which respectively move along the axis of the non-deflected beamimpinging thereon. The mirror 1701 moves in the direction 1704, whichshall be the y-direction here, as well as in direction 1703, which shallbe the x-direction, and the mirror 1702 in direction 1703, thus thex-direction, which here is arranged perpendicular to the y-direction1704. The movement of the mirrors 1701 and 1702 is thereby coupled tothe movement of the focusing optical system.

FIG. 5 shows details of a z-scan module 1400, which comprises a fastz-scanner 401 and a slow z-scanner 411. A first beam-widening telescopeis thereby configured as the fast z-scanner 401. It contains a lens 1101movable along the z-direction, which is oscillated about its zeroposition in a fast manner. It is advantageous to arrange such a fastoscillating lens, as shown here, in the beam path near the radiationsource 100, as the beam still has a small diameter here, and thismovable lens 1101 can be designed as a smallest, lightest element atthis location. A negative, thus concave lens as the movable lens 1101 ofthe beam-widening telescope effects an oscillation of the beamdivergence with a constant beam diameter in the exit pupil 1201.

A relay telescope 1200 images the exit pupil 1201 of the fast z-scanner401 into the entrance pupil 1204 of a further beam-widening telescope1300. This further beam-widening telescope 1300 is designed as a slowz-scanner 411 with an optional z-t-curve and a wide scanning range insuch a manner that the entire height z of the processing volume 300 (seeFIG. 4) can be scanned. For this, the lens 1301 can be moved in acontrolled manner with arbitrary location-time curves, but limited inspeed and acceleration.

In the exit pupil 1303 of this z-scan module 1400, a beam with anoptionally slowly adjustable divergence is then available in a wideadjustment range 1320 with a fixed beam diameter, whose divergenceadditionally oscillates with a fixed amplitude given by the amplitude ofthe oscillation of the lens 1101 in a smaller angle range or adjustmentrange 1310 about the zero position with the slow but optionally movablelens 1301.

FIG. 6 shows the divergence change with a movement of the focus 4 in thez-direction. The focusing optical system 200 transmits the fastdivergence oscillation in the angle range 1310, which is caused by thefast z-scanner, and the slow divergence variation in the angle range1320, which is caused by the slow z-scanner, into an oscillation of thez-position of the focus 4 in the z-area 1710 and variation of the zeroposition of the oscillation in the z-area 1720. The aperture angle ofthe focused beam, thus the numeric aperture NA, remains constant whenthe exit pupil 1303 of the slow scanner 411 is placed into the entrancepupil of the focusing optical system 200.

In FIG. 7, the principal structure of a scan pattern is illustrated foran area 11 to be processed in a three-dimensional processing volume of atransparent material, concerning a multiple curved incision area 11 inthis example, which is to be generated using a pulsed laser radiation.

Such a scan pattern consists of individual strokes 7 which arerespectively realized by a sequence of laser focus effective zones 8 ona scan line 5. The individual strokes 7 are lined up in rows to thedesired incision area 11 so that they fill the incision area 11 and thatthe individual laser focus effective zones 8 have an approximately samedistance 9 not only to their preceding and subsequent laser focuseffective zones 8 on the same stroke 7, but also to the laser focuseffective zones 8 of the adjacent strokes 7, wherein fluctuations of thedistance, for example, by a factor of 2, are unproblematic. Here, eachstroke 7 remains within the currently accessible section of the opticalsystem 2, 200, but may slowly displace for forming the area 11. Theincision area 11 then has a “band-shaped” form.

Due to the flexibility of scanning movements, thus the possibility formovement in an arbitrary direction in the processing volume 300, and inparticular when using a system which enables a fast scanning movement inan arbitrary direction in a section 600 of the processing volume 300independently of a slow scanning movement in an arbitrary direction inthe processing volume 300, an arbitrary curvature with a high qualitycan be achieved by an advantageous arrangement of the individual strokes7.

The strokes 7 are realized in this example by a synchronous oscillatorymovement of a fast z-scanner 401 and the fast lateral scanner 402, 403,that is, a fast x-scanner 402 and a fast y-scanner 403. One of thesescanners 401, 402, 403 may be a resonant scanner, the other must be ableto the synchronized to its resonant frequency.

The scan pattern results from the placement of the scan lines 5 of theindividual strokes 7 next to each other. This is effected by a slowscanning movement by use of the slow deflection system or scanningsystem, 411, 412, 413, which contains a slow x-scanner, a slow y-scannerand a slow z-scanner, with which the optical system 2, 200 itself ismoved. By a combination of slow scanning movement and fast oscillatorymovement, the center position of the oscillatory movement is displacedslowly in an arbitrary desired direction in the processing volume 300.

FIGS. 8a to 8c illustrate the different situations for the position ofthe focal cone 6 of a focused laser radiation to be realized for a laserfocus effective zone 8, 82 to the laser focus effective zones 8, 81already realized in different scan patterns. The focal cone 6 isunderstood to mean only the part visually marked with a bracket in thesefigures, not the other cone, which results in the beam direction behindthe laser focus effective zone 8, 81, 82 by the “divergence” of theradiation.

In FIG. 8a , in which the laser focus effective zones 8, as alreadyshown in the prior art and FIG. 1b , are placed along a vertical scanline 5, the scan pattern is thus constructed in columns, the focal cone6 of yet to be realized laser focus effective zones 8, 82 projects intolaser focus effective zones 8, 81 that are already realized of thestrokes 7 that are already realized and thereby leads to shadowing.

Laser focus effective zones 8, 81 that are already realized shouldtherefore not be in the focal cone 6 of the laser focus 4 for the laserfocus effective zones 8, 82 still to be realized. With a line-by-lineconstruction of the scan pattern, starting with the bottom line as shownin FIG. 8b , this is always given. However, a shadowing problem by laserfocus effective zones 8, 81 already realized occurs then at least in theedge regions of a partial area already generated 11 to a next partialarea of a processing area 11 to be generated—as already described above.

By an inclination of the scan lines 5 and thus of the strokes 7 suchthat the inclination angle α of the strokes 7 to the beam axis 12 islarger than the focal angle φ, that is, the angle between a straightline extending on the cone surface of the focal cone 6 and the beam axis12, and such a sequence of the individual strokes 7, an inclined stroke7 still to be realized is generated in the positive z-direction, thusagainst the beam direction of the focused radiation above an inclinedstroke 7 already realized, as shown in FIG. 8c , any shadowing effect oflaser focus effective zones 8, 81 already realized for laser focuseffective zones 8, 82 still to be realized is avoided. With anappropriate inclination angle α of the strokes 7 or the scan line 5 onwhich the stroke 7 shall be realized, the placement of the laser focus 4at an arbitrary location of the scan line 5 of the stroke 7 to berealized is possible in such a manner that the scan line 5 penetratesthe focal cone 6 of the laser radiation only in the focal point 4. Thescan pattern of FIG. 8c may be generated as shown in detail in FIG. 10.

FIG. 9 shows the advantageous side-by-side placement of inclined strokes7 for processing a closed, cylindrical area 11. Therein, the strokes 7are placed side-by-side such that existing strokes 7 from the part ofthe scan pattern already realized do not penetrate the focal cone 6 ofthe laser radiation, but only the diverging further cone in regionsbehind the laser focus 4. The processing of the area 11 is therefore notobstructed by shadowings generated by existing strokes 7.

In order to be able to close the area 11, without laser focus effectivezones 8, 81 already realized reaching into the focal cone 6 of the focus4 for laser focus effective zones 8, 82 still to be realized, the firststrokes 7 should be encoded as shown in the region 22 of FIG. 9. A line23 passing the starting points of the first side-by-side realizedstrokes 7 with a distance 10 to each other should form an angle α with astraight line in the z-direction, which is parallel to the base positionbeam axis 12, which angle is larger than the focal angle φ. In order tofinally close the area 11, these first strokes 7 of the region 22 arerespectively prolonged by a second stroke 7 so that the desired totalheight in the z-direction is reached.

The inclined strokes 7 or the inclined scan lines 5 with an inclinationangle α which is larger than the focal angle φ, have a sufficientlylarge z-dimension despite their inclination for efficient filling of theprocessing area 11 with the laser focus effective zones 8.

In the following, the generation of an inclined scan line 5 and inclinedstrokes 7 is now described by synchronous change-of-direction-movements,in particular by synchronous oscillatory movements, of a fast z-scanner401 and at least one of the fast lateral scanners 402, 403.

In FIG. 10, the superimposition of a sinusoidal oscillation of the fastz-scanner is initially shown with a synchronous sinusoidal oscillationof a fast lateral scanner in the x-direction with a slow change of theoscillation center point in the positive x-direction for generatingstraight strokes 7.

A sinusoidal oscillation of a fast z-scanner 401, which is shown in thez-t-diagram on the top left, is superimposed with a synchronoussinusoidal oscillation of a fast x-scanner 402 with a slow change of theoscillation center point, which is shown in the x-t-diagram on bottomright, to an inclined scan pattern as shown in the z-x-diagram topright. All points initially represent potential shooting positions of ashort pulse laser used for this, because of its repetition rate, thuslaser focus effective zones 8. The triangles thereby mark the actuallyrealized, thus not blocked, laser focus effective zones 8, 81. In thiscase, the laser focus effective zones are only realized in the upwardmovement 14. Laser pulses at the reversal points of the sinusoidalmovement and in the downward movement are masked.

The fast scanners for the z-direction and for the lateral spatialdirections x- and/or y carry out synchronous sinusoidal oscillationswithout phase shift. An exact opposite phase oscillation can be realizedby a negative amplitude. The path of the laser focus 4 then describes atotal scanning line 5. If in addition a movement is carried out by theslow scanning system or the center of oscillation of the oscillation ischanged slowly, the scan line 5 moves through the processing volume 300during its generation and leaves a “wound” sinusoidal curve in theprocessing volume 300:

${\overset{\rightarrow}{r}(t)} = {\begin{pmatrix}{x(t)} \\{y(t)} \\{z(t)}\end{pmatrix} = {{\begin{pmatrix}A_{x} \\A_{y} \\A_{z}\end{pmatrix}{\sin\left( {2\;\pi\; f_{s}t} \right)}} + {\begin{pmatrix}v_{x} \\v_{y} \\v_{z}\end{pmatrix}t} + \begin{pmatrix}x_{0} \\y_{0} \\z_{0}\end{pmatrix}}}$

f_(s) is the frequency of the sinusoidal oscillation of the scanner. Theslow movement can locally be linearly approximated. The x-, y- andz-components of the current amplitude of the oscillation A_(x), A_(y),A_(z), the x-, y- and z-components of the current speed of the slowscanning movement v_(x), v_(y), v_(z), and the current position, thusthe starting position in the space, x_(o), y_(o) and z_(o) are, comparedwith the oscillation period of the fast scanners, so slowly temporallychangeable that they can be assumed to be constant for a period ofoscillation.

If the laser emits pulses with a fixed repetition rate, laser focuseffective zones 8 with a spot-to-spot-distance, thus a distance of thetwo laser focus effective zones dS, 9 are generated in the space. Thespot-to-spot-distances dS, 9 vary with the current position of thesinusoidal oscillation and are largest in the zero passage of theoscillation and almost zero in the reversing points.

A good approximation for dS is:

${dS} = {{\frac{d\; r}{d\; t}} \cdot \frac{1}{f_{L}}}$

f_(L) is the laser pulse repetition rate which is an integer part of thebasic repetition rate of the laser. It is, depending on the duty cycleof the pulses every first, every second, every third pulse, etc. It is:

$\frac{d\;{\overset{\rightarrow}{r}(t)}}{d\; t} = {{2\;\pi\;{f_{s}\begin{pmatrix}A_{x} \\A_{y} \\A_{z}\end{pmatrix}}{\cos\left( {2\;\pi\; f_{s}t} \right)}} + \begin{pmatrix}v_{x} \\v_{y} \\v_{z}\end{pmatrix}}$

dS is in the zero transitions:

$\hat{dS} = {{\frac{2\;\pi\; f_{S}}{f_{L}}{\begin{pmatrix}A_{x} \\A_{y} \\A_{z}\end{pmatrix}}} + {{\begin{pmatrix}v_{x} \\v_{y} \\v_{z}\end{pmatrix}}.}}$

By masking the laser pulses, and thus the laser focus effective zones 8,83, in the reversal points, an excessive variation of thespot-to-spot-distances dS, 9, and in particular the realization of laserfocus effective zones in a too large proximity to each other can beavoided. For example, the laser pulses can be masked when the distancebetween two laser focus effective zones, thus the spot-to-spot-distancedS, has fallen to about half of the value at the zero transition, thuswhen:

cos(2πf _(s) t)=±1/2.

The “hatching width” as the actual height of the strokes 7, thus thepart of the scan line, on which laser focus effective zones 8 were orare realized are, is then

2 sin(arccos ½)=√{square root over (3)}=1.73

thus, 1.73 times of the amplitude of the oscillation A:

$A = {{\begin{pmatrix}A_{x} \\A_{y} \\A_{z}\end{pmatrix}}.}$

The distance between two adjacent “hatching” lines dT, 10 and thus twostrokes 7 is, in the case, that cuts are only carried out in oneoscillation direction, that is upwards 14 or downwards 15, is constantover an oscillation:

${dT} = {\frac{v}{f_{L}} = {\frac{1}{f_{L}}{{\begin{pmatrix}v_{x} \\v_{y} \\v_{z}\end{pmatrix}}.}}}$

FIG. 11 shows the superposition of a sinusoidal oscillation of the fastz-scanner with a synchronous sinusoidal oscillation of a fast lateralscanner in the x-direction with a slow change of the oscillation centerpoint in the negative x-direction for the bidirectional generation ofstrokes 7.

In contrast to the example of FIG. 10, the strokes are generated here 7on an inclined scan line 5 with a bidirectional laser incision in boththe upward movement 14 and in the downward movement 15, see strokes 7with upward pointing triangles for the upward movement and strokes 7with downward pointing triangles for the downward movement in order tomark the corresponding laser focus effective zones 8.

In the bidirectional incision mode, the distance between two strokes dT,10 also varies with the respective position on the scan line 5, but ishalf as large in the zero transitions as with the unidirectionalincision mode of FIG. 10. If, as in the unidirectional case, one cuts at√3/2 of the amplitude, with which the distance between two laser focuseffective zones dS falls to half of the maximum value at the zerotransition, the line spacing and thus the distance dT, 10 of two strokes7 alternately varies from ⅓ and to 5/3 of the value in the zerotransition. The distance 2 dT to the second nearest straight scan line5, and thus to the second nearest stroke 5, remains constant 6/3 as inthe unidirectional mode.

If the strokes 7 are to be introduced such that subsequent strokes stillto be realized are arranged “over” the previously realized strokes 7, sothat strokes 7 already realized do not shadow the focal cone 6 of thelaser focus 4, the lateral oscillation, must be carried out in phaseopposition to the z-oscillation for a positive slow movement in thex-direction as shown in FIG. 10, and the fast lateral oscillation in thex-direction must be carried out in phase to the fast z-oscillation for anegative movement in x-direction as shown in FIG. 11.

If a capsulotomy incision shall be carried out, there is the objectiveto generate an incision area 11 that cuts through the anterior skin ofthe lens of an eye, the so-called “anterior capsule” in a selectablehole geometry. This geometry can for example be elliptical or circular.The incision area 11 shall thereby extend with a minimum distance aboveand below the capsular bag, in order to ensure a safe cut.

For executing such an incision, there are different possible scanpatterns for the focus 4 of a pulsed laser beam, which is used for“cutting”. A first possibility is shown in FIG. 12. FIG. 12 shows afirst scan pattern for generating a capsulotomy incision, in which theslow movement follows laterally the hole geometry 17 and follows thez-height 18 of the capsular bag in the z-direction.

A fast oscillatory scanning movement in the z-direction is synchronizedwith fast oscillatory scanning movements tangentially to the lateralslow scanning movement 13, thus straight to the lateral component of theslow scanning movement 13, for forming the strokes 7, thus the laserfocus effective zones 8 realized on a scan line 5 in the same direction.These effect therein a separation of the eye material 3 by photodisruption and thus contribute to the formation of an incision area 11.The image of a “lattice fence” inclined in the “fence direction”results.

At the top right in FIG. 12, a schematic diagram in plan view shows thatthe strokes 7 are aligned in the direction of progress of the slowscanning movement 13. The lower end of such a stroke 7 which is drawnthin, precedes the slow movement 13, the upper end, which is drawnthick, remains behind the slow movement 13, so that the focal cone 6 ofthe laser focus 4 for the laser focus effective zones 8 of thesubsequent stroke 7 is never shadowed by strokes 7 already realized. Atthe point where the end of the incision area 11 shall meet again thestarting point, the strokes 7 are limited at the beginning in such amanner that a V-shaped region remains free for forming the last strokes7, which then fill up the initially incomplete strokes 7.

FIG. 13 shows a second scan pattern for generating a capsulotomyincision, in which the slow movement follows laterally along the holegeometry 17 and in the z-direction of the z-height 18 of the capsularbag.

A fast oscillatory scanning movement in the z-direction is synchronizedto a lateral fast oscillatory scanning movement normal to the lateralslow scanning movement 13, that is, perpendicular to the lateralcomponent of the slow scanning movement 13, for forming the strokes 7,that means the laser focus effective zones 8 realized on a scan line 5in the same direction. These also effect a separation of the eyematerial 3 by photo disruption and thus contribute to the formation ofan incision area 11. The image of an outwardly inclined “lattice fence”results thereof.

The top right in FIG. 13 shows a schematic diagram in plan view, in thatthe strokes 7 are aligned vertically to the advancement of the slowscanning movement 13. They always spare the zone for the focal cone 6 ofthe laser focus 4 for the subsequent stroke 7 free, regardless if thestroke 7 of the slow scanning movement 13 points up in the inside oroutside area, as long as the condition that the angle of inclination aof the stroke 7 is larger than the focal angle φ of the focal cone 6 ofthe laser focus 4, described in FIG. 8c , is realized.

FIG. 14 shows a third scan pattern for generating a capsulotomyincision. A fast oscillatory scanning movement in the z-direction issynchronized to a lateral fast oscillatory scanning movement, which iscarried out to the lateral slow scanning movement 13 at an angle betweenthe tangential and the normal direction. This leads to the formation ofthe strokes 7, which also cause a separation of the eye material 3 byphoto disruption and thus contribute to the formation of an incisionarea 11. Thus, an image similar to obliquely outwardly inclined but notfallen “pick-a-stick” game pieces results.

The top right in FIG. 14 shows a schematic diagram in plan view, in thatthe strokes 7 are aligned at an angle between the tangential and normalalignment to the progress of the slow scanning movement 13. The part ofthe strokes 7 preceding the slow scanning movement 13 which is drawnthin, is the end lower end of the strokes 7, and the thick-drawn part,which remains behind the slow scanning movement 13, is the upper end ofthe strokes 7. Thereby, the focal cone 6 of the laser focus 4 for thesubsequent stroke 7 is not shadowed by stroke 7 already realized,provided that the condition is fulfilled that the angle of inclination aof the strokes 7 is larger than the focal angle φ of the focal cone 6 ofthe laser focus 4.

The scan pattern of FIG. 12 is the preferred example scan pattern forgenerating a capsulotomy incision. The hole geometry 17 essentiallyremains the same even if the capsular bag to be cut is no longersituated exactly at the planned position at the time of the incision,which might happen due to inaccuracies of measurement or a subsequentmovement of the eye media, while with the scan patterns of FIGS. 13 and14, the diameter of the capsulotomy incision actually realized dependson the actual z-position of the overlap of the incision area 11 with thecapsular bag, thus a transparent eye material 3.

In practice, the scan pattern of FIG. 12 is also the one with thehighest incision efficiency, thus the highest incision performance withthe smallest laser energies and/or with the largest distances 9 of twolaser focus effective areas 8.

FIGS. 15a to 15c show various stages of a scan pattern for generating alens fragmentation incision that again results from photo disruptionusing a pulsed laser beam. FIGS. 15d and 15e show a further solution fora corresponding scan pattern for completing the incision planes atcrossing points.

The pulsed laser beam is usually realized here as for many otherophthalmologic purposes, too, with a femtosecond laser. Ideally, for theuse for eye surgical purposes here as well as in the examples of FIGS.12, 13, 14, 16, 17 and 18 a system for processing an area 11 in aprocessing volume 300 of a transparent material 3, as described in FIG.3, is used, thus, in particular a system which permits a fast scanningmovement in any direction in a section 600 of the processing volume 300independently of a slow scanning movement in any direction in the entireprocessing volume 300, wherein the section 600 of the fast scanningmovements is moved by the slow scanning movement through the processingvolume 300.

But it is also possible, with appropriate adjustments, for example tosimulate the interaction of the fast scanning movement with a slowscanning movement, to transfer it to a single scanning system, ifnecessary with considerable loss of speed, and thus to use othersystems, such as the system for processing an area 11 in a processingvolume 300 of a transparent material 3, as described in FIG. 19.

For the lens fragmentation, an incision area 11 has to be generated thatdivides a lens of an eye along freely selectable incision planes 19, 20.The incision planes 19, 20 should thereby comply with minimum distancesto the edges of the lens, thus follow the curvature of the limiting lenssurfaces above and below.

For the formation of an extended incision area 11, which cuts throughthe entire volume of the lens, the stroke of a fast scanning movement,in particular the stroke determined by the amplitude of an oscillatorymovement of a fast z-scanner, is not sufficient to divide the lenscompletely.

In this case, the total incision area must be composed of several singleincision bands 21. If a complete incision plane 19, 20 shall begenerated in a processing volume 300, whose form is thus relevant overthe entire plane, unlike to capsulotomy, where only the penetration ofthe capsular bag is relevant, the individual strokes 7 and thus the scanlines have to be arranged in this incision region 11. The strokes 7 thusmust be inevitably inclined in the direction of progress of the slowmovement 13 or inclined against the direction of progress of the slowmovement 13, that is, analogous to the first scan pattern of thecapsulotomy.

Again, a part of the laser pulses is masked, in order to prevent damageby the realization of two laser focus effective zones in closeproximity. The laser pulses are always masked, in addition to thereversal points of the fast oscillatory scanning movements which arecarried out by the fast scanners, when the scan line leaves the intendedincision region of the incision planes 19, 20 at full amplitude of theoscillation. In order to not shadowing a subsequent incision band 21 byan individual incision band 21, all deep-seated incision bands 21 arecreated first, before proceeding with higher-seated bands 21, as shownin FIG. 15b . Thus, there is a floor type configuration. The completedpattern of the entire incision area 11 can be seen in FIG. 15c . At thepenetration points of two incision bands 21 there is also a shadowing ofthe subsequently realized incision band 21 by the already completedincision band 21. Here, a conical region can first be left blank at thepenetration point, which can be filled up from the bottom upwards onlyusing the fast scanner after completion of the complete “floor”.

FIGS. 15d and 15e illustrate once more the problem occurring atintersection of two incision planes, as shown here for two crossedincision planes of a lens fragmentation incision, and show anothersolution for an appropriate scan pattern for completing the incisionplanes at intersections: After the crossing incision bands 21 weregenerated with a funnel-shaped recess at the crossing point, as shown inFIG. 15d , which corresponds to a focal cone 6 of the laser focus 4, thefunnel is completed by a cross-cut band 21 in the tunnel-shaped recess,which is generated by fast lateral oscillatory scanning movements and aslow z-scanning movement, as becomes apparent from the FIG. 15 e.

In FIGS. 15a to 15c , superimposed incision bands 21 are inclined indifferent directions. The inclination directions depend on the progressdirection of the slow scanning movement 13. The progress directions ofthe slow scanning movement 13 selected in FIG. 15a to FIG. 15c arethereby not mandatory, but can usually be chosen freely, however, thepresence of already realized incision bands 21 possibly leads to apreferred direction of the slow scanning movement 13 for an incisionband 21 still to be realized. Superimposed incision bands 21, which areinclined in the same direction because they are cut in the samedirection 13 are also within the scope of the invention.

A scan pattern for generating an arcuate incision, that is an arcuateincision profile that can, for example, be used for the relaxation andcorrection of an astigmatism of an eye, is shown in FIGS. 16a to 16c indifferent views: FIG. 16a shows a plan view, FIG. 16b an obliqueprojection and FIG. 16c is a side view of a scan pattern and incisionpattern, which is suitable for an arcuate incision.

For an arcuate incision an incision area in the form of a sloping,curved incision band 24 must be generated. This is solved in analogy tothe scan patterns of FIGS. 13 and 14 for the capsulotomy, wherein theoblique position, that the inclination of each stroke 7, can be changedcontinuously, the start and end points, thus for example the height inthe z-direction, at which the corresponding stroke 7 starts and ends,can be continuously varied, and starting angle and ending angle 26, 25of the curved incision band 24 are freely selected.

The strokes 7 extend radially starting from an axis, as shown in theplan view of FIG. 16 a.

The incision band 24 starts at a starting angle 25 and ends with an endangle 26. The start and end points of each stroke 7 at its respectiveangular position, for example, is given by the distance from the axis 27and a z-height 28 and may change continually when passing through theangle range from the starting angle 25 to the end angle 26. Thus, theinclination, the length and the position of the strokes 7 can be adaptedto the geometry of the eye tissue 3 to be cut. Since for thisapplication, the incision band, or the incision area 24, unlike for thecapsulotomy, shall be generated in the volume of the eye tissue, thefree choice of the form of the incision area 24 is of high importancehere.

A first and a second scan pattern for generating an access incision thatis an access incision in the context of an ophthalmological treatmentprocess is finally shown in different phases in FIGS. 17a to 17c andFIGS. 18a to 18 c.

Such access incision or “access tunnel” shall be generated with adesired width, inclination and with appropriate “bending edges” forforming a self-sealing incision geometry passing the cornea of the eye3.

Even if an access incision can be carried out with oblique strokes 7, itdoes not necessarily require a z-portion of the fast oscillatoryscanning movement, since the scan vertical to the access direction 30 asshown in FIG. 17a , or parallel to the access direction 30 as shown inFIG. 18a can be carried out laterally in an x-y plane.

In some cases, the amplitude of the lateral oscillatory scanningmovement is smaller than the required width of the tunnel. The incisionarea must then be dissected into sections 31, which are carried outsequentially.

In particular, the section 31 started in FIG. 17a reaches the maximumwidth of the oscillatory scanning movement at the end. In the phase ofFIG. 17b , therefore, the tunnel is divided into two adjacent regions 31and processed consecutively. A further subdivision, e.g. at bendingedges 29, may be advantageous.

As shown in FIGS. 17c and 18c , the next plane is started only aftercompletion of the flat region that has been processed in an x-y plane.The slow scanning system can thereby remain in a fixed position duringthe execution of the strokes 7 and only subsequently go to the nextposition after the completion of a section: The slow lateral scannerdoes not have to be used for a progression during the processing of anincision area: This can also be done by a slow zero position shift ofthe oscillation of the fast scanners.

When generating the inclined plane, the consideration of the size of theinclination angle compared to the focal angle is in turn necessary, inorder to avoid shadowing effects. If necessary, it must also be filledobliquely here, as already suggested for FIGS. 14 and 15 b and shown inFIG. 9.

Due to the slow movement of the oscillation center in the accessdirection, the individual strokes 7 are realized side by side. Bymasking the focus effective zones 8 of the laser pulses when theoscillation movement passes over the edges of the sections, thedimensional accuracy of the incision area 11, 31 is ensured with anarbitrarily chosen width course over the access direction 30.

FIG. 19 shows a second example of a system for processing an area in aprocessing volume of a transparent material by application of a focusedradiation.

The system includes a device for generating a radiation 100 comprising afemtosecond laser with a wavelength in the range of 1020 nm to 1060 nm.The pulse duration of this femtosecond laser is between 500 fs to 600fs, the pulse energy is about 10 μJ.

In addition, the system comprises an optical system 2, 200 for focusingthe radiation in a focus 4, with a numerical aperture of 0.2, which hasa field of view of about 6 mm. With this system, a processing volume 600of 6 mm×6 mm×6 mm can be obtained.

The system shown here comprises a device for changing the position 400of the focus 4 with a scanning system that can carry out scanningmovements in the x-, y- and z-directions and may execute a scanningmovement in any direction by the composition of these scanningmovements. The device for changing the position 400 comprises threescanners 411, 412, 413, which possibly can displace the opticsaccordingly. However, since it comprises no second fast scanning system,which is independently adjustable from the first scanning system, thescan patterns presented here can be only be realized under loss of timein such a system.

Furthermore, the system comprises a one-piece central control system500, which is connected to the device for generating a radiation 100,thus the femtosecond laser system, and connected with the device forchanging the position 400 of the focus 4 via communication paths 501,and is configured to control the femtosecond laser system and allscanners 411, 412, 413 of the device for changing the position 400 ofthe focus 4.

Despite a lack of an additional fast scanning system, it is possiblewith such a scanning system to realize example scan patterns such thatshadowing effects of the scan pattern already realized do not orminimally result for scan patterns still to be realized, whencorresponding scan patterns are encoded in the control device 500 ofthis system. Thereby, working in a very limited local volume at anymoment—as realized here—is advantageous in eye surgery, for example, tominimize the effects of a possible movement of the eye during thesurgery in the eye tissue 3.

The control value for each scanning direction is thereby composed ofslow, wide-ranging base components in the three spatial directions witharbitrary timing within these limits, and short-range, fast repetitivecomponents corresponding to synchronous change-of-direction-movements inthe three spatial directions and whose time course only slightly changesin each repetition.

The characteristics mentioned above and explained in various exemplaryembodiments of the invention can thereby not only be applied in thecombinations shown in the examples, but also in other combinations oralone, without leaving the scope of the present invention.

A description based on system characteristics applies with respect tothese features analogously to the corresponding method, while methodcharacteristics represent corresponding functional characteristics ofthe described system.

Various embodiments of systems, devices, and methods have been describedherein. These embodiments are given only by way of example and are notintended to limit the scope of the claimed inventions. It should beappreciated, moreover, that the various features of the embodiments thathave been described may be combined in various ways to produce numerousadditional embodiments. Moreover, while various materials, dimensions,shapes, configurations and locations, etc. have been described for usewith disclosed embodiments, others besides those disclosed may beutilized without exceeding the scope of the claimed inventions.

Persons of ordinary skill in the relevant arts will recognize that thesubject matter hereof may comprise fewer features than illustrated inany individual embodiment described above. The embodiments describedherein are not meant to be an exhaustive presentation of the ways inwhich the various features of the subject matter hereof may be combined.Accordingly, the embodiments are not mutually exclusive combinations offeatures; rather, the various embodiments can comprise a combination ofdifferent individual features selected from different individualembodiments, as understood by persons of ordinary skill in the art.Moreover, elements described with respect to one embodiment can beimplemented in other embodiments even when not described in suchembodiments unless otherwise noted.

Although a dependent claim may refer in the claims to a specificcombination with one or more other claims, other embodiments can alsoinclude a combination of the dependent claim with the subject matter ofeach other dependent claim or a combination of one or more features withother dependent or independent claims. Such combinations are proposedherein unless it is stated that a specific combination is not intended.

Any incorporation by reference of documents above is limited such thatno subject matter is incorporated that is contrary to the explicitdisclosure herein. Any incorporation by reference of documents above isfurther limited such that no claims included in the documents areincorporated by reference herein. Any incorporation by reference ofdocuments above is yet further limited such that any definitionsprovided in the documents are not incorporated by reference hereinunless expressly included herein.

For purposes of interpreting the claims, it is expressly intended thatthe provisions of 35 U.S.C. § 112(f) are not to be invoked unless thespecific terms “means for” or “step for” are recited in a claim.

1. (canceled)
 2. An ophthalmologic therapy system for processing aportion of a processing volume of a transparent material of an eye byapplication of focused radiation, comprising a device that generatesradiation; an optical system that focuses the radiation at a focus inthe processing volume, wherein the focus of the focused radiation has afocal angle (φ) and the focused radiation is directed along a beam axis;a scanner that changes position of the focus in the processing volume,which can be described with three spatial directions x, y and z, whereinthe z-direction proceeds parallel to the beam axis of the focusedradiation; a controller that controls the ophthalmologic therapy system;wherein the controller is encoded with a scan pattern, which scanpattern includes adjacent strokes with each adjacent stroke having anangle of inclination (α) to the beam axis; and wherein the angle ofinclination (α) of the strokes to the beam axis is always larger than orequal to the focal angle (φ) of the focused radiation.
 3. Theophthalmologic therapy system as claimed in claim 2, wherein the strokecomprises a straight part of a scan line and is formed by stringingtogether focus effective zones of the focused radiation.
 4. Theophthalmologic therapy system as claimed in claim 2, the encoded scanpattern in the control device further being such that the formation ofthe strokes through stringing together focus effective zones of thefocused radiation is always formed in an upward movement or always in adownward movement or alternatively in an upward movement and in adownward movement implemented along the scan line.
 5. The ophthalmologictherapy system as claimed in claim 2, the encoded scan pattern in thecontrol device further being such that the adjacent strokes areseparated by an essentially constant distance that can vary by severalpercent.
 6. The ophthalmologic therapy system as claimed in claim 2, theencoded scan pattern in the control device further being such that atleast some of the strokes are curved.
 7. The ophthalmologic therapysystem as claimed in claim 2, the encoded scan pattern in the controldevice further being such that the angle of inclination of the strokesto the beam axis is larger than the focal angle of the focusedradiation, such that a focus effective zone already realized is also notarranged in the cone area of the focal cone of a focus effective zonestill to be realized.
 8. The ophthalmologic therapy system as claimed inclaim 2, the encoded scan pattern in the control device further beingsuch that the angle of inclination of the strokes to the beam axis islarger than the focal angle of the focused radiation applies for eachindividual stroke and at any point of the stroke.
 9. The ophthalmologictherapy system as claimed in claim 8, the encoded scan pattern in thecontrol device further being such that at least some of the strokes arecurved.
 10. A method of processing a portion of a processing volume of atransparent material of an eye by application of focused radiationapplied by an ophthalmologic therapy system which comprises a devicethat generates the focused radiation, and an optical system that focusesthe radiation at a focus in the processing volume which can be describedwith three spatial directions x, y and z, wherein the focus of thefocused radiation comprises a focal angle (φ) and the focused radiationcomprises a beam axis, the method comprising: generating a scan patternwhich has mutually adjacent strokes with angles of inclination (α) tothe beam axis, wherein a stroke comprises a section of a scan line andis formed by stringing together focus effective zones of the focusedradiation, wherein the angle of inclination (α) of the strokes to thebeam axis is larger or equal to a focal angle (φ) of the focusedradiation; changing a position of the focus on a basis of the scanpattern by scanning movement by operation of at least a first scanner ina section of the processing volume determined by the three spatialdirections; and generating the mutually adjacent strokes of the scanpattern in the transparent material by application of the focusedradiation to the transparent material at points along a scan line. 11.The method as claimed in claim 10, further comprising generating themutually adjacent strokes of the scan pattern in the transparentmaterial by application of the focused radiation to the transparentmaterial at points along a scan line formed by stringing together focuseffective zones of the focused radiation.
 12. The method as claimed inclaim 10, further comprising generating the mutually adjacent strokes ofthe scan pattern in the transparent material by application of thefocused radiation to the transparent material such that the adjacentstrokes are separated by an essentially constant distance that can varyby several percent.
 13. The method as claimed in claim 10, furthercomprising generating the mutually adjacent strokes of the scan patternin the transparent material by application of the focused radiation tothe transparent material such that at least some of the strokes arecurved.
 14. The method as claimed in claim 10, further comprisinggenerating the mutually adjacent strokes of the scan pattern in thetransparent material by application of the focused radiation to thetransparent material such that the angle of inclination of the strokesto the beam axis is larger than the focal angle of the focusedradiation, such that a focus effective zone already realized is also notarranged in the cone area of the focal cone of a focus effective zonestill to be realized.
 15. The method as claimed in claim 10, furthercomprising generating the mutually adjacent strokes of the scan patternin the transparent material by application of the focused radiation tothe transparent material such that the angle of inclination of thestrokes to the beam axis is larger than the focal angle of the focusedradiation applies for each individual stroke and at any point of thestroke.
 16. The method as claimed in claim 10, further comprisinggenerating the mutually adjacent strokes of the scan pattern in thetransparent material by application of the focused radiation to thetransparent material such that at least some of the strokes are curved.17. The method as claimed in claim 10, further comprising generating themutually adjacent strokes of the scan pattern in the transparentmaterial by application of the focused radiation to the transparentmaterial such that the formation of the strokes through stringingtogether focus effective zones of the focused radiation is always formedin a downward movement.
 18. The method as claimed in claim 10, furthercomprising generating the mutually adjacent strokes of the scan patternin the transparent material by application of the focused radiation tothe transparent material such that the formation of the strokes throughstringing together focus effective zones of the focused radiation isalways formed in an upward movement.
 19. The method as claimed in claim10, further comprising generating the mutually adjacent strokes of thescan pattern in the transparent material by application of the focusedradiation to the transparent material such that the formation of thestrokes through stringing together focus effective zones of the focusedradiation is formed alternatively in an upward movement and in adownward movement implemented along the scan line.
 20. The method asclaimed in claim 10, further comprising generating the mutually adjacentstrokes of the scan pattern in the transparent material by applicationof the focused radiation to the transparent material such that thestroke comprises a straight part of a scan line.
 21. The method asclaimed in claim 10, further comprising generating the mutually adjacentstrokes of the scan pattern in the transparent material by applicationof the focused radiation to the transparent material such that thestroke comprises curvatures or deviations from a straight line of one ormore degrees.